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* rhashtable: Avoid calculating hash again to unlockThomas Graf2015-03-161-6/+5
| | | | | | | | Caching the lock pointer avoids having to hash on the object again to unlock the bucket locks. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Annotate RCU locking of walkersThomas Graf2015-03-161-0/+2
| | | | | | | | | | | Fixes the following sparse warnings: lib/rhashtable.c:767:5: warning: context imbalance in 'rhashtable_walk_start' - wrong count at exit lib/rhashtable.c:849:6: warning: context imbalance in 'rhashtable_walk_stop' - unexpected unlock Fixes: f2dba9c6ff0d ("rhashtable: Introduce rhashtable_walk_*") Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Fix rhashtable_remove failuresHerbert Xu2015-03-161-10/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | The commit 9d901bc05153bbf33b5da2cd6266865e531f0545 ("rhashtable: Free bucket tables asynchronously after rehash") causes gratuitous failures in rhashtable_remove. The reason is that it inadvertently introduced multiple rehashing from the perspective of readers. IOW it is now possible to see more than two tables during a single RCU critical section. Fortunately the other reader rhashtable_lookup already deals with this correctly thanks to c4db8848af6af92f90462258603be844baeab44d ("rhashtable: rhashtable: Move future_tbl into struct bucket_table") so only rhashtable_remove is broken by this change. This patch fixes this by looping over every table from the first one to the last or until we find the element that we were trying to delete. Incidentally the simple test for detecting rehashing to prevent starting another shrinking no longer works. Since it isn't needed anyway (the work queue and the mutex serves as a natural barrier to unnecessary rehashes) I've simply killed the test. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Fix use-after-free in rhashtable_walk_stopHerbert Xu2015-03-161-3/+4
| | | | | | | | | | | | | | | The commit c4db8848af6af92f90462258603be844baeab44d ("rhashtable: Move future_tbl into struct bucket_table") introduced a use-after- free bug in rhashtable_walk_stop because it dereferences tbl after droping the RCU read lock. This patch fixes it by moving the RCU read unlock down to the bottom of rhashtable_walk_stop. In fact this was how I had it originally but it got dropped while rearranging patches because this one depended on the async freeing of bucket_table. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Move future_tbl into struct bucket_tableHerbert Xu2015-03-151-16/+11
| | | | | | | | This patch moves future_tbl to open up the possibility of having multiple rehashes on the same table. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Add rehash counter to bucket_tableHerbert Xu2015-03-152-1/+2
| | | | | | | | | | | | | | | This patch adds a rehash counter to bucket_table to indicate the last bucket that has been rehashed. This serves two purposes: 1. Any bucket that has been rehashed can never gain a new object. 2. If the rehash counter reaches the size of the table, the table will forever remain empty. This patch also downsizes bucket_table->size to an unsigned int since we do not support sizes greater than 32 bits yet. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Free bucket tables asynchronously after rehashHerbert Xu2015-03-151-3/+6
| | | | | | | | | | | | There is in fact no need to wait for an RCU grace period in the rehash function, since all insertions are guaranteed to go into the new table through spin locks. This patch uses call_rcu to free the old/rehashed table at our leisure. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Move seed init into bucket_table_allocHerbert Xu2015-03-151-10/+6
| | | | | | | | | | | It seems that I have already made every rehash redo the random seed even though my commit message indicated otherwise :) Since we have already taken that step, this patch goes one step further and moves the seed initialisation into bucket_table_alloc. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Use SINGLE_DEPTH_NESTINGHerbert Xu2015-03-151-7/+2
| | | | | | | | We only nest one level deep there is no need to roll our own subclasses. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Fix walker behaviour during rehashHerbert Xu2015-03-151-23/+46
| | | | | | | | | | | | | | | | | | | | Previously whenever the walker encountered a resize it simply snaps back to the beginning and starts again. However, this only works if the rehash started and completed while the walker was idle. If the walker attempts to restart while the rehash is still ongoing, we may miss objects that we shouldn't have. This patch fixes this by making the walker walk the old table followed by the new table just like all other readers. If a rehash is detected we will still signal our caller of the fact so they can prepare for duplicates but we will simply continue the walk onto the new table after the old one is finished either by us or by the rehasher. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Fix read-side crash during rehashHerbert Xu2015-03-131-1/+1
| | | | | | | | | | This patch fixes a typo rhashtable_lookup_compare where we fail to recompute the hash when looking up the new table. This causes elements to be missed and potentially a crash during a resize. Reported-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: kill ht->shift atomic operationsDaniel Borkmann2015-03-131-30/+25
| | | | | | | | | | | | | | | | | | | | | Commit c0c09bfdc415 ("rhashtable: avoid unnecessary wakeup for worker queue") changed ht->shift to be atomic, which is actually unnecessary. Instead of leaving the current shift in the core rhashtable structure, it can be cached inside the individual bucket tables. There, it will only be initialized once during a new table allocation in the shrink/expansion slow path, and from then onward it stays immutable for the rest of the bucket table liftime. That allows shift to be non-atomic. The patch also moves hash_rnd management into the table setup. The rhashtable structure now consumes 3 instead of 4 cachelines. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Ying Xue <ying.xue@windriver.com> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Fix reader/rehash raceHerbert Xu2015-03-131-0/+6
| | | | | | | | | | | | There is a potential race condition between readers and the rehasher. In particular, the rehasher could have started a rehash while the reader finishes a scan of the old table but fails to see the new table pointer. This patch closes this window by adding smp_wmb/smp_rmb. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Remove obj_raw_hashfnHerbert Xu2015-03-121-18/+7
| | | | | | | | | | | | Now that the only caller of obj_raw_hashfn is head_hashfn, we can simply kill it and fold it into the latter. This patch also moves the common shift from head_hashfn/key_hashfn into rht_bucket_index. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Remove key length argument to key_hashfnHerbert Xu2015-03-121-3/+4
| | | | | | | | | key_hashfn has only one caller and it doesn't really need to supply the key length as an extra parameter. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Use head_hashfn instead of obj_raw_hashfnHerbert Xu2015-03-121-7/+5
| | | | | | | | | | Now that we don't have cross-table hashes, we no longer need to keep the entire hash value so all users of obj_raw_hashfn can use head_hashfn instead. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Move masking back into key_hashfnHerbert Xu2015-03-121-2/+3
| | | | | | | | | | This patch reverts commit c88455ce50ae4224d84960ce2baa53e61580df27 ("rhashtable: key_hashfn() must return full hash value") because the only user of it always masks the hash value. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Add annotation to nested lockHerbert Xu2015-03-121-2/+2
| | | | | | | | | | Commit aa34a6cb0478842452bac58edb50d3ef9e178c92 ("rhashtable: Add arbitrary rehash function") killed the annotation on the nested lock which leads to bitching from lockdep. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Add arbitrary rehash functionHerbert Xu2015-03-111-332/+174
| | | | | | | | | | | | | | | | | This patch adds a rehash function that supports the use of any hash function for the new table. This is needed to support changing the random seed value during the lifetime of the hash table. However for now the random seed value is still constant and the rehash function is simply used to replace the existing expand/shrink functions. [ ASSERT_BUCKET_LOCK() and thus debug_dump_table() + debug_dump_buckets() are not longer used, so delete them entirely. -DaveM ] Signed-off-by: Herbert Xu <herbert.xu@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* rhashtable: Move hash_rnd into bucket_tableHerbert Xu2015-03-111-9/+15
| | | | | | | | | | | | | | | Currently hash_rnd is a parameter that users can set. However, no existing users set this parameter. It is also something that people are unlikely to want to set directly since it's just a random number. In preparation for allowing the reseeding/rehashing of rhashtable, this patch moves hash_rnd into bucket_table so that it's now an internal state rather than a parameter. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge tag 'trace-fixes-v4.0-rc2-2' of ↵Linus Torvalds2015-03-101-2/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull seq-buf/ftrace fixes from Steven Rostedt: "This includes fixes for seq_buf_bprintf() truncation issue. It also contains fixes to ftrace when /proc/sys/kernel/ftrace_enabled and function tracing are started. Doing the following causes some issues: # echo 0 > /proc/sys/kernel/ftrace_enabled # echo function_graph > /sys/kernel/debug/tracing/current_tracer # echo 1 > /proc/sys/kernel/ftrace_enabled # echo nop > /sys/kernel/debug/tracing/current_tracer # echo function_graph > /sys/kernel/debug/tracing/current_tracer As well as with function tracing too. Pratyush Anand first reported this issue to me and supplied a patch. When I tested this on my x86 test box, it caused thousands of backtraces and warnings to appear in dmesg, which also caused a denial of service (a warning for every function that was listed). I applied Pratyush's patch but it did not fix the issue for me. I looked into it and found a slight problem with trampoline accounting. I fixed it and sent Pratyush a patch, but he said that it did not fix the issue for him. I later learned tha Pratyush was using an ARM64 server, and when I tested on my ARM board, I was able to reproduce the same issue as Pratyush. After applying his patch, it fixed the problem. The above test uncovered two different bugs, one in x86 and one in ARM and ARM64. As this looked like it would affect PowerPC, I tested it on my PPC64 box. It too broke, but neither the patch that fixed ARM or x86 fixed this box (the changes were all in generic code!). The above test, uncovered two more bugs that affected PowerPC. Again, the changes were only done to generic code. It's the way the arch code expected things to be done that was different between the archs. Some where more sensitive than others. The rest of this series fixes the PPC bugs as well" * tag 'trace-fixes-v4.0-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Fix ftrace enable ordering of sysctl ftrace_enabled ftrace: Fix en(dis)able graph caller when en(dis)abling record via sysctl ftrace: Clear REGS_EN and TRAMP_EN flags on disabling record via sysctl seq_buf: Fix seq_buf_bprintf() truncation seq_buf: Fix seq_buf_vprintf() truncation
| * seq_buf: Fix seq_buf_bprintf() truncationSteven Rostedt (Red Hat)2015-03-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In seq_buf_bprintf(), bstr_printf() is used to copy the format into the buffer remaining in the seq_buf structure. The return of bstr_printf() is the amount of characters written to the buffer excluding the '\0', unless the line was truncated! If the line copied does not fit, it is truncated, and a '\0' is added to the end of the buffer. But in this case, '\0' is included in the length of the line written. To know if the buffer had overflowed, the return length will be the same or greater than the length of the buffer passed in. The check in seq_buf_bprintf() only checked if the length returned from bstr_printf() would fit in the buffer, as the seq_buf_bprintf() is only to be an all or nothing command. It either writes all the string into the seq_buf, or none of it. If the string is truncated, the pointers inside the seq_buf must be reset to what they were when the function was called. This is not the case. On overflow, it copies only part of the string. The fix is to change the overflow check to see if the length returned from bstr_printf() is less than the length remaining in the seq_buf buffer, and not if it is less than or equal to as it currently does. Then seq_buf_bprintf() will know if the write from bstr_printf() was truncated or not. Link: http://lkml.kernel.org/r/1425500481.2712.27.camel@perches.com Cc: stable@vger.kernel.org Reported-by: Joe Perches <joe@perches.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * seq_buf: Fix seq_buf_vprintf() truncationSteven Rostedt (Red Hat)2015-03-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In seq_buf_vprintf(), vsnprintf() is used to copy the format into the buffer remaining in the seq_buf structure. The return of vsnprintf() is the amount of characters written to the buffer excluding the '\0', unless the line was truncated! If the line copied does not fit, it is truncated, and a '\0' is added to the end of the buffer. But in this case, '\0' is included in the length of the line written. To know if the buffer had overflowed, the return length will be the same as the length of the buffer passed in. The check in seq_buf_vprintf() only checked if the length returned from vsnprintf() would fit in the buffer, as the seq_buf_vprintf() is only to be an all or nothing command. It either writes all the string into the seq_buf, or none of it. If the string is truncated, the pointers inside the seq_buf must be reset to what they were when the function was called. This is not the case. On overflow, it copies only part of the string. The fix is to change the overflow check to see if the length returned from vsnprintf() is less than the length remaining in the seq_buf buffer, and not if it is less than or equal to as it currently does. Then seq_buf_vprintf() will know if the write from vsnpritnf() was truncated or not. Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds2015-03-042-37/+36
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull networking fixes from David Miller: 1) If an IPVS tunnel is created with a mixed-family destination address, it cannot be removed. Fix from Alexey Andriyanov. 2) Fix module refcount underflow in netfilter's nft_compat, from Pablo Neira Ayuso. 3) Generic statistics infrastructure can reference variables sitting on a released function stack, therefore use dynamic allocation always. Fix from Ignacy Gawędzki. 4) skb_copy_bits() return value test is inverted in ip_check_defrag(). 5) Fix network namespace exit in openvswitch, we have to release all of the per-net vports. From Pravin B Shelar. 6) Fix signedness bug in CAIF's cfpkt_iterate(), from Dan Carpenter. 7) Fix rhashtable grow/shrink behavior, only expand during inserts and shrink during deletes. From Daniel Borkmann. 8) Netdevice names with semicolons should never be allowed, because they serve as a separator. From Matthew Thode. 9) Use {,__}set_current_state() where appropriate, from Fabian Frederick. 10) Revert byte queue limits support in r8169 driver, it's causing regressions we can't figure out. 11) tcp_should_expand_sndbuf() erroneously uses tp->packets_out to measure packets in flight, properly use tcp_packets_in_flight() instead. From Neal Cardwell. 12) Fix accidental removal of support for bluetooth in CSR based Intel wireless cards. From Marcel Holtmann. 13) We accidently added a behavioral change between native and compat tasks, wrt testing the MSG_CMSG_COMPAT bit. Just ignore it if the user happened to set it in a native binary as that was always the behavior we had. From Catalin Marinas. 14) Check genlmsg_unicast() return valud in hwsim netlink tx frame handling, from Bob Copeland. 15) Fix stale ->radar_required setting in mac80211 that can prevent starting new scans, from Eliad Peller. 16) Fix memory leak in nl80211 monitor, from Johannes Berg. 17) Fix race in TX index handling in xen-netback, from David Vrabel. 18) Don't enable interrupts in amx-xgbe driver until all software et al. state is ready for the interrupt handler to run. From Thomas Lendacky. 19) Add missing netlink_ns_capable() checks to rtnl_newlink(), from Eric W Biederman. 20) The amount of header space needed in macvtap was not calculated properly, fix it otherwise we splat past the beginning of the packet. From Eric Dumazet. 21) Fix bcmgenet TCP TX perf regression, from Jaedon Shin. 22) Don't raw initialize or mod timers, use setup_timer() and mod_timer() instead. From Vaishali Thakkar. 23) Fix software maintained statistics in bcmgenet and systemport drivers, from Florian Fainelli. 24) DMA descriptor updates in sh_eth need proper memory barriers, from Ben Hutchings. 25) Don't do UDP Fragmentation Offload on RAW sockets, from Michal Kubecek. 26) Openvswitch's non-masked set actions aren't constructed properly into netlink messages, fix from Joe Stringer. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (116 commits) openvswitch: Fix serialization of non-masked set actions. gianfar: Reduce logging noise seen due to phy polling if link is down ibmveth: Add function to enable live MAC address changes net: bridge: add compile-time assert for cb struct size udp: only allow UFO for packets from SOCK_DGRAM sockets sh_eth: Really fix padding of short frames on TX Revert "sh_eth: Enable Rx descriptor word 0 shift for r8a7790" sh_eth: Fix RX recovery on R-Car in case of RX ring underrun sh_eth: Ensure proper ordering of descriptor active bit write/read net/mlx4_en: Disbale GRO for incoming loopback/selftest packets net/mlx4_core: Fix wrong mask and error flow for the update-qp command net: systemport: fix software maintained statistics net: bcmgenet: fix software maintained statistics rxrpc: don't multiply with HZ twice rxrpc: terminate retrans loop when sending of skb fails net/hsr: Fix NULL pointer dereference and refcnt bugs when deleting a HSR interface. net: pasemi: Use setup_timer and mod_timer net: stmmac: Use setup_timer and mod_timer net: 8390: axnet_cs: Use setup_timer and mod_timer net: 8390: pcnet_cs: Use setup_timer and mod_timer ...
| * rhashtable: use cond_resched()Eric Dumazet2015-02-271-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a hash table has 128 slots and 16384 elems, expand to 256 slots takes more than one second. For larger sets, a soft lockup is detected. Holding cpu for that long, even in a work queue is a show stopper for non preemptable kernels. cond_resched() at strategic points to allow process scheduler to reschedule us. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
| * rhashtable: remove indirection for grow/shrink decision functionsDaniel Borkmann2015-02-272-39/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, all real users of rhashtable default their grow and shrink decision functions to rht_grow_above_75() and rht_shrink_below_30(), so that there's currently no need to have this explicitly selectable. It can/should be generic and private inside rhashtable until a real use case pops up. Since we can make this private, we'll save us this additional indirection layer and can improve insertion/deletion time as well. Reference: http://patchwork.ozlabs.org/patch/443040/ Suggested-by: David S. Miller <davem@davemloft.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
| * rhashtable: unconditionally grow when max_shift is not specifiedDaniel Borkmann2015-02-272-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While commit c0c09bfdc415 ("rhashtable: avoid unnecessary wakeup for worker queue") rightfully moved part of the decision making of whether we should expand or shrink from the expand/shrink functions themselves into insert/delete functions in order to avoid unnecessary worker wake-ups, it however introduced a regression by doing so. Before that change, if no max_shift was specified (= 0) on rhashtable initialization, rhashtable_expand() would just grow unconditionally and lets the available memory be the limiting factor. After that change, if no max_shift was specified, there would be _no_ expansion step at all. Given that netlink and tipc have a max_shift specified, it was not visible there, but Josh Hunt reported that if nft that starts out with a default element hint of 3 if not otherwise provided, would slow i.e. inserts down trememdously as it cannot grow larger to relax table occupancy. Given that the test case verifies shrinks/expands manually, we also must remove pointer to the helper functions to explicitly avoid parallel resizing on insertions/deletions. test_bucket_stats() and test_rht_lookup() could also be wrapped around rhashtable mutex to explicitly synchronize a walk from resizing, but I think that defeats the actual test case which intended to have explicit test steps, i.e. 1) inserts, 2) expands, 3) shrinks, 4) deletions, with object verification after each stage. Reported-by: Josh Hunt <johunt@akamai.com> Fixes: c0c09bfdc415 ("rhashtable: avoid unnecessary wakeup for worker queue") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Ying Xue <ying.xue@windriver.com> Cc: Josh Hunt <johunt@akamai.com> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
| * rhashtable: initialize all rhashtable walker membersSasha Levin2015-02-231-0/+3
| | | | | | | | | | | | | | | | | | | | Commit f2dba9c6ff ("rhashtable: Introduce rhashtable_walk_*") forgot to initialize the members of struct rhashtable_walker after allocating it, which caused an undefined value for 'resize' which is used later on. Fixes: f2dba9c6ff ("rhashtable: Introduce rhashtable_walk_*") Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * rhashtable: allow to unload test moduleDaniel Borkmann2015-02-201-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's no good reason why to disallow unloading of the rhashtable test case module. Commit 9d6dbe1bbaf8 moved the code from a boot test into a stand-alone module, but only converted the subsys_initcall() handler into a module_init() function without a related exit handler, and thus preventing the test module from unloading. Fixes: 9d6dbe1bbaf8 ("rhashtable: Make selftest modular") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
| * rhashtable: better high order allocation attemptsDaniel Borkmann2015-02-201-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When trying to allocate future tables via bucket_table_alloc(), it seems overkill on large table shifts that we probe for kzalloc() unconditionally first, as it's likely to fail. Only probe with kzalloc() for more reasonable table sizes and use vzalloc() either as a fallback on failure or directly in case of large table sizes. Fixes: 7e1e77636e36 ("lib: Resizable, Scalable, Concurrent Hash Table") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
| * rhashtable: don't test for shrink on insert, expansion on deleteDaniel Borkmann2015-02-201-9/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Restore pre 54c5b7d311c8 behaviour and only probe for expansions on inserts and shrinks on deletes. Currently, it will happen that on initial inserts into a sparse hash table, we may i.e. shrink it first simply because it's not fully populated yet, only to later realize that we need to grow again. This however is counter intuitive, e.g. an initial default size of 64 elements is already small enough, and in case an elements size hint is given to the hash table by a user, we should avoid unnecessary expansion steps, so a shrink is clearly unintended here. Fixes: 54c5b7d311c8 ("rhashtable: introduce rhashtable_wakeup_worker helper function") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Ying Xue <ying.xue@windriver.com> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
| * rhashtable: don't allocate ht structure on stack in test_rht_initDaniel Borkmann2015-02-201-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With object runtime debugging enabled, the rhashtable test suite will rightfully throw a warning "ODEBUG: object is on stack, but not annotated" from rhashtable_init(). This is because run_work is (correctly) being initialized via INIT_WORK(), and not annotated by INIT_WORK_ONSTACK(). Meaning, rhashtable_init() is okay as is, we just need to move ht e.g., into global scope. It never triggered anything, since test_rhashtable is rather a controlled environment and effectively runs to completion, so that stack memory is not vanishing underneath us, we shouldn't confuse any testers with it though. Fixes: 7e1e77636e36 ("lib: Resizable, Scalable, Concurrent Hash Table") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge branch 'kconfig' of ↵Linus Torvalds2015-02-191-15/+15
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kconfig updates from Michal Marek: "Yann E Morin was supposed to take over kconfig maintainership, but this hasn't happened. So I'm sending a few kconfig patches that I collected: - Fix for missing va_end in kconfig - merge_config.sh displays used if given too few arguments - s/boolean/bool/ in Kconfig files for consistency, with the plan to only support bool in the future" * 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kconfig: use va_end to match corresponding va_start merge_config.sh: Display usage if given too few arguments kconfig: use bool instead of boolean for type definition attributes
| * | kconfig: use bool instead of boolean for type definition attributesChristoph Jaeger2015-01-071-15/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Support for keyword 'boolean' will be dropped later on. No functional change. Reference: http://lkml.kernel.org/r/cover.1418003065.git.cj@linux.com Signed-off-by: Christoph Jaeger <cj@linux.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
* | | Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds2015-02-181-5/+30
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull virtio updates from Rusty Russell: "OK, this has the big virtio 1.0 implementation, as specified by OASIS. On top of tht is the major rework of lguest, to use PCI and virtio 1.0, to double-check the implementation. Then comes the inevitable fixes and cleanups from that work" * tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (80 commits) virtio: don't set VIRTIO_CONFIG_S_DRIVER_OK twice. virtio_net: unconditionally define struct virtio_net_hdr_v1. tools/lguest: don't use legacy definitions for net device in example launcher. virtio: Don't expose legacy net features when VIRTIO_NET_NO_LEGACY defined. tools/lguest: use common error macros in the example launcher. tools/lguest: give virtqueues names for better error messages tools/lguest: more documentation and checking of virtio 1.0 compliance. lguest: don't look in console features to find emerg_wr. tools/lguest: don't start devices until DRIVER_OK status set. tools/lguest: handle indirect partway through chain. tools/lguest: insert driver references from the 1.0 spec (4.1 Virtio Over PCI) tools/lguest: insert device references from the 1.0 spec (4.1 Virtio Over PCI) tools/lguest: rename virtio_pci_cfg_cap field to match spec. tools/lguest: fix features_accepted logic in example launcher. tools/lguest: handle device reset correctly in example launcher. virtual: Documentation: simplify and generalize paravirt_ops.txt lguest: remove NOTIFY call and eventfd facility. lguest: remove NOTIFY facility from demonstration launcher. lguest: use the PCI console device's emerg_wr for early boot messages. lguest: always put console in PCI slot #1. ...
| * | pci: add pci_iomap_rangeMichael S. Tsirkin2015-01-211-5/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Virtio drivers should map the part of the BAR they need, not necessarily all of it. Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-pci@vger.kernel.org Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | | Merge branch 'for-linus' of ↵Linus Torvalds2015-02-171-8/+28
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc VFS updates from Al Viro: "This cycle a lot of stuff sits on topical branches, so I'll be sending more or less one pull request per branch. This is the first pile; more to follow in a few. In this one are several misc commits from early in the cycle (before I went for separate branches), plus the rework of mntput/dput ordering on umount, switching to use of fs_pin instead of convoluted games in namespace_unlock()" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: switch the IO-triggering parts of umount to fs_pin new fs_pin killing logics allow attaching fs_pin to a group not associated with some superblock get rid of the second argument of acct_kill() take count and rcu_head out of fs_pin dcache: let the dentry count go down to zero without taking d_lock pull bumping refcount into ->kill() kill pin_put() mode_t whack-a-mole: chelsio file->f_path.dentry is pinned down for as long as the file is open... get rid of lustre_dump_dentry() gut proc_register() a bit kill d_validate() ncpfs: get rid of d_validate() nonsense selinuxfs: don't open-code d_genocide()
| * | | dcache: let the dentry count go down to zero without taking d_lockLinus Torvalds2015-01-261-8/+28
| |/ / | | | | | | | | | | | | | | | | | | We can be more aggressive about this, if we are clever and careful. This is subtle. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | scripts/gdb: add infrastructureJan Kiszka2015-02-171-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This provides the basic infrastructure to load kernel-specific python helper scripts when debugging the kernel in gdb. The loading mechanism is based on gdb loading for <objfile>-gdb.py when opening <objfile>. Therefore, this places a corresponding link to the main helper script into the output directory that contains vmlinux. The main scripts will pull in submodules containing Linux specific gdb commands and functions. To avoid polluting the source directory with compiled python modules, we link to them from the object directory. Due to gdb.parse_and_eval and string redirection for gdb.execute, we depend on gdb >= 7.2. This feature is enabled via CONFIG_GDB_SCRIPTS. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Acked-by: Michal Marek <mmarek@suse.cz> [kbuild stuff] Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ben Widawsky <ben@bwidawsk.net> Cc: Borislav Petkov <bp@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | lib/Kconfig: use bool instead of booleanChristoph Jaeger2015-02-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Keyword 'boolean' for type definition attributes is considered deprecated and, therefore, should not be used anymore. See http://lkml.kernel.org/r/cover.1418003065.git.cj@linux.com See http://lkml.kernel.org/r/1419108071-11607-1-git-send-email-cj@linux.com Signed-off-by: Christoph Jaeger <cj@linux.com> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6Linus Torvalds2015-02-141-0/+5
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull crypto update from Herbert Xu: "Here is the crypto update for 3.20: - Added 192/256-bit key support to aesni GCM. - Added MIPS OCTEON MD5 support. - Fixed hwrng starvation and race conditions. - Added note that memzero_explicit is not a subsitute for memset. - Added user-space interface for crypto_rng. - Misc fixes" * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (71 commits) crypto: tcrypt - do not allocate iv on stack for aead speed tests crypto: testmgr - limit IV copy length in aead tests crypto: tcrypt - fix buflen reminder calculation crypto: testmgr - mark rfc4106(gcm(aes)) as fips_allowed crypto: caam - fix resource clean-up on error path for caam_jr_init crypto: caam - pair irq map and dispose in the same function crypto: ccp - terminate ccp_support array with empty element crypto: caam - remove unused local variable crypto: caam - remove dead code crypto: caam - don't emit ICV check failures to dmesg hwrng: virtio - drop extra empty line crypto: replace scatterwalk_sg_next with sg_next crypto: atmel - Free memory in error path crypto: doc - remove colons in comments crypto: seqiv - Ensure that IV size is at least 8 bytes crypto: cts - Weed out non-CBC algorithms MAINTAINERS: add linux-crypto to hw random crypto: cts - Remove bogus use of seqiv crypto: qat - don't need qat_auth_state struct crypto: algif_rng - fix sparse non static symbol warning ...
| * | | lib: memzero_explicit: add comment for its usageDaniel Borkmann2015-01-081-0/+5
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | Lets improve the comment to add a note on when to use memzero_explicit() for those not digging through the git logs. We don't want people to pollute places with memzero_explicit() where it's not really necessary. Reference: https://lkml.org/lkml/2015/1/4/190 Suggested-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* | | kasan: enable instrumentation of global variablesAndrey Ryabinin2015-02-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This feature let us to detect accesses out of bounds of global variables. This will work as for globals in kernel image, so for globals in modules. Currently this won't work for symbols in user-specified sections (e.g. __init, __read_mostly, ...) The idea of this is simple. Compiler increases each global variable by redzone size and add constructors invoking __asan_register_globals() function. Information about global variable (address, size, size with redzone ...) passed to __asan_register_globals() so we could poison variable's redzone. This patch also forces module_alloc() to return 8*PAGE_SIZE aligned address making shadow memory handling ( kasan_module_alloc()/kasan_module_free() ) more simple. Such alignment guarantees that each shadow page backing modules address space correspond to only one module_alloc() allocation. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | lib: add kasan test moduleAndrey Ryabinin2015-02-143-3/+289
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a test module doing various nasty things like out of bounds accesses, use after free. It is useful for testing kernel debugging features like kernel address sanitizer. It mostly concentrates on testing of slab allocator, but we might want to add more different stuff here in future (like stack/global variables out of bounds accesses and so on). Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | mm: slub: add kernel address sanitizer support for slub allocatorAndrey Ryabinin2015-02-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With this patch kasan will be able to catch bugs in memory allocated by slub. Initially all objects in newly allocated slab page, marked as redzone. Later, when allocation of slub object happens, requested by caller number of bytes marked as accessible, and the rest of the object (including slub's metadata) marked as redzone (inaccessible). We also mark object as accessible if ksize was called for this object. There is some places in kernel where ksize function is called to inquire size of really allocated area. Such callers could validly access whole allocated memory, so it should be marked as accessible. Code in slub.c and slab_common.c files could validly access to object's metadata, so instrumentation for this files are disabled. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Signed-off-by: Dmitry Chernenkov <dmitryc@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | x86_64: add KASan supportAndrey Ryabinin2015-02-141-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds arch specific code for kernel address sanitizer. 16TB of virtual addressed used for shadow memory. It's located in range [ffffec0000000000 - fffffc0000000000] between vmemmap and %esp fixup stacks. At early stage we map whole shadow region with zero page. Latter, after pages mapped to direct mapping address range we unmap zero pages from corresponding shadow (see kasan_map_shadow()) and allocate and map a real shadow memory reusing vmemmap_populate() function. Also replace __pa with __pa_nodebug before shadow initialized. __pa with CONFIG_DEBUG_VIRTUAL=y make external function call (__phys_addr) __phys_addr is instrumented, so __asan_load could be called before shadow area initialized. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Jim Davis <jim.epost@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | kasan: add kernel address sanitizer infrastructureAndrey Ryabinin2015-02-142-0/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kernel Address sanitizer (KASan) is a dynamic memory error detector. It provides fast and comprehensive solution for finding use-after-free and out-of-bounds bugs. KASAN uses compile-time instrumentation for checking every memory access, therefore GCC > v4.9.2 required. v4.9.2 almost works, but has issues with putting symbol aliases into the wrong section, which breaks kasan instrumentation of globals. This patch only adds infrastructure for kernel address sanitizer. It's not available for use yet. The idea and some code was borrowed from [1]. Basic idea: The main idea of KASAN is to use shadow memory to record whether each byte of memory is safe to access or not, and use compiler's instrumentation to check the shadow memory on each memory access. Address sanitizer uses 1/8 of the memory addressable in kernel for shadow memory and uses direct mapping with a scale and offset to translate a memory address to its corresponding shadow address. Here is function to translate address to corresponding shadow address: unsigned long kasan_mem_to_shadow(unsigned long addr) { return (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET; } where KASAN_SHADOW_SCALE_SHIFT = 3. So for every 8 bytes there is one corresponding byte of shadow memory. The following encoding used for each shadow byte: 0 means that all 8 bytes of the corresponding memory region are valid for access; k (1 <= k <= 7) means that the first k bytes are valid for access, and other (8 - k) bytes are not; Any negative value indicates that the entire 8-bytes are inaccessible. Different negative values used to distinguish between different kinds of inaccessible memory (redzones, freed memory) (see mm/kasan/kasan.h). To be able to detect accesses to bad memory we need a special compiler. Such compiler inserts a specific function calls (__asan_load*(addr), __asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16. These functions check whether memory region is valid to access or not by checking corresponding shadow memory. If access is not valid an error printed. Historical background of the address sanitizer from Dmitry Vyukov: "We've developed the set of tools, AddressSanitizer (Asan), ThreadSanitizer and MemorySanitizer, for user space. We actively use them for testing inside of Google (continuous testing, fuzzing, running prod services). To date the tools have found more than 10'000 scary bugs in Chromium, Google internal codebase and various open-source projects (Firefox, OpenSSL, gcc, clang, ffmpeg, MySQL and lots of others): [2] [3] [4]. The tools are part of both gcc and clang compilers. We have not yet done massive testing under the Kernel AddressSanitizer (it's kind of chicken and egg problem, you need it to be upstream to start applying it extensively). To date it has found about 50 bugs. Bugs that we've found in upstream kernel are listed in [5]. We've also found ~20 bugs in out internal version of the kernel. Also people from Samsung and Oracle have found some. [...] As others noted, the main feature of AddressSanitizer is its performance due to inline compiler instrumentation and simple linear shadow memory. User-space Asan has ~2x slowdown on computational programs and ~2x memory consumption increase. Taking into account that kernel usually consumes only small fraction of CPU and memory when running real user-space programs, I would expect that kernel Asan will have ~10-30% slowdown and similar memory consumption increase (when we finish all tuning). I agree that Asan can well replace kmemcheck. We have plans to start working on Kernel MemorySanitizer that finds uses of unitialized memory. Asan+Msan will provide feature-parity with kmemcheck. As others noted, Asan will unlikely replace debug slab and pagealloc that can be enabled at runtime. Asan uses compiler instrumentation, so even if it is disabled, it still incurs visible overheads. Asan technology is easily portable to other architectures. Compiler instrumentation is fully portable. Runtime has some arch-dependent parts like shadow mapping and atomic operation interception. They are relatively easy to port." Comparison with other debugging features: ======================================== KMEMCHECK: - KASan can do almost everything that kmemcheck can. KASan uses compile-time instrumentation, which makes it significantly faster than kmemcheck. The only advantage of kmemcheck over KASan is detection of uninitialized memory reads. Some brief performance testing showed that kasan could be x500-x600 times faster than kmemcheck: $ netperf -l 30 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec no debug: 87380 16384 16384 30.00 41624.72 kasan inline: 87380 16384 16384 30.00 12870.54 kasan outline: 87380 16384 16384 30.00 10586.39 kmemcheck: 87380 16384 16384 30.03 20.23 - Also kmemcheck couldn't work on several CPUs. It always sets number of CPUs to 1. KASan doesn't have such limitation. DEBUG_PAGEALLOC: - KASan is slower than DEBUG_PAGEALLOC, but KASan works on sub-page granularity level, so it able to find more bugs. SLUB_DEBUG (poisoning, redzones): - SLUB_DEBUG has lower overhead than KASan. - SLUB_DEBUG in most cases are not able to detect bad reads, KASan able to detect both reads and writes. - In some cases (e.g. redzone overwritten) SLUB_DEBUG detect bugs only on allocation/freeing of object. KASan catch bugs right before it will happen, so we always know exact place of first bad read/write. [1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel [2] https://code.google.com/p/address-sanitizer/wiki/FoundBugs [3] https://code.google.com/p/thread-sanitizer/wiki/FoundBugs [4] https://code.google.com/p/memory-sanitizer/wiki/FoundBugs [5] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel#Trophies Based on work by Andrey Konovalov. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Acked-by: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Cc: Yuri Gribov <tetra2005@gmail.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | bitmap, cpumask, nodemask: remove dedicated formatting functionsTejun Heo2015-02-142-77/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that all bitmap formatting usages have been converted to '%*pb[l]', the separate formatting functions are unnecessary. The following functions are removed. * bitmap_scn[list]printf() * cpumask_scnprintf(), cpulist_scnprintf() * [__]nodemask_scnprintf(), [__]nodelist_scnprintf() * seq_bitmap[_list](), seq_cpumask[_list](), seq_nodemask[_list]() * seq_buf_bitmask() Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | bitmap: use %*pb[l] to print bitmaps including cpumasks and nodemasksTejun Heo2015-02-141-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | printk and friends can now format bitmaps using '%*pb[l]'. cpumask and nodemask also provide cpumask_pr_args() and nodemask_pr_args() respectively which can be used to generate the two printf arguments necessary to format the specified cpu/nodemask. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | lib/vsprintf: implement bitmap printing through '%*pb[l]'Tejun Heo2015-02-142-59/+96
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bitmap and its derivatives such as cpumask and nodemask currently only provide formatting functions which put the output string into the provided buffer; however, how long this buffer should be isn't defined anywhere and given that some of these bitmaps can be too large to be formatted into an on-stack buffer it users sometimes are unnecessarily forced to come up with creative solutions and compromises for the buffer just to printk these bitmaps. There have been a couple different attempts at making this easier. 1. Way back, PeterZ tried printk '%pb' extension with the precision for bit width - '%.*pb'. This was intuitive and made sense but unfortunately triggered a compile warning about using precision for a pointer. http://lkml.kernel.org/g/1336577562.2527.58.camel@twins 2. I implemented bitmap_pr_cont[_list]() and its wrappers for cpumask and nodemask. This works but PeterZ pointed out that pr_cont's tendency to produce broken lines when multiple CPUs are printing is bothering considering the usages. http://lkml.kernel.org/g/1418226774-30215-3-git-send-email-tj@kernel.org So, this patch is another attempt at teaching printk and friends how to print bitmaps. It's almost identical to what PeterZ tried with precision but it uses the field width for the number of bits instead of precision. The format used is '%*pb[l]', with the optional trailing 'l' specifying list format instead of hex masks. This is a valid format string and doesn't trigger compiler warnings; however, it does make it impossible to specify output field width when printing bitmaps. I think this is an acceptable trade-off given how much easier it makes printing bitmaps and that we don't have any in-kernel user which is using the field width specification. If any future user wants to use field width with a bitmap, it'd have to format the bitmap into a string buffer and then print that buffer with width spec, which isn't different from how it should be done now. This patch implements bitmap[_list]_string() which are called from the vsprintf pointer() formatting function. The implementation is mostly identical to bitmap_scn[list]printf() except that the output is performed in the vsprintf way. These functions handle formatting into too small buffers and sprintf() family of functions report the correct overrun output length. bitmap_scn[list]printf() are now thin wrappers around scnprintf(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Chris Zankel <chris@zankel.net> Cc: Christoph Lameter <cl@linux.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Mike Travis <travis@sgi.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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