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GFP_NOFS context is used for the following 5 reasons currently:
- to prevent from deadlocks when the lock held by the allocation
context would be needed during the memory reclaim
- to prevent from stack overflows during the reclaim because the
allocation is performed from a deep context already
- to prevent lockups when the allocation context depends on other
reclaimers to make a forward progress indirectly
- just in case because this would be safe from the fs POV
- silence lockdep false positives
Unfortunately overuse of this allocation context brings some problems to
the MM. Memory reclaim is much weaker (especially during heavy FS
metadata workloads), OOM killer cannot be invoked because the MM layer
doesn't have enough information about how much memory is freeable by the
FS layer.
In many cases it is far from clear why the weaker context is even used
and so it might be used unnecessarily. We would like to get rid of
those as much as possible. One way to do that is to use the flag in
scopes rather than isolated cases. Such a scope is declared when really
necessary, tracked per task and all the allocation requests from within
the context will simply inherit the GFP_NOFS semantic.
Not only this is easier to understand and maintain because there are
much less problematic contexts than specific allocation requests, this
also helps code paths where FS layer interacts with other layers (e.g.
crypto, security modules, MM etc...) and there is no easy way to convey
the allocation context between the layers.
Introduce memalloc_nofs_{save,restore} API to control the scope of
GFP_NOFS allocation context. This is basically copying
memalloc_noio_{save,restore} API we have for other restricted allocation
context GFP_NOIO. The PF_MEMALLOC_NOFS flag already exists and it is
just an alias for PF_FSTRANS which has been xfs specific until recently.
There are no more PF_FSTRANS users anymore so let's just drop it.
PF_MEMALLOC_NOFS is now checked in the MM layer and drops __GFP_FS
implicitly same as PF_MEMALLOC_NOIO drops __GFP_IO. memalloc_noio_flags
is renamed to current_gfp_context because it now cares about both
PF_MEMALLOC_NOFS and PF_MEMALLOC_NOIO contexts. Xfs code paths preserve
their semantic. kmem_flags_convert() doesn't need to evaluate the flag
anymore.
This patch shouldn't introduce any functional changes.
Let's hope that filesystems will drop direct GFP_NOFS (resp. ~__GFP_FS)
usage as much as possible and only use a properly documented
memalloc_nofs_{save,restore} checkpoints where they are appropriate.
[akpm@linux-foundation.org: fix comment typo, reflow comment]
Link: http://lkml.kernel.org/r/20170306131408.9828-5-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The current implementation of the reclaim lockup detection can lead to
false positives and those even happen and usually lead to tweak the code
to silence the lockdep by using GFP_NOFS even though the context can use
__GFP_FS just fine.
See
http://lkml.kernel.org/r/20160512080321.GA18496@dastard
as an example.
=================================
[ INFO: inconsistent lock state ]
4.5.0-rc2+ #4 Tainted: G O
---------------------------------
inconsistent {RECLAIM_FS-ON-R} -> {IN-RECLAIM_FS-W} usage.
kswapd0/543 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&xfs_nondir_ilock_class){++++-+}, at: xfs_ilock+0x177/0x200 [xfs]
{RECLAIM_FS-ON-R} state was registered at:
mark_held_locks+0x79/0xa0
lockdep_trace_alloc+0xb3/0x100
kmem_cache_alloc+0x33/0x230
kmem_zone_alloc+0x81/0x120 [xfs]
xfs_refcountbt_init_cursor+0x3e/0xa0 [xfs]
__xfs_refcount_find_shared+0x75/0x580 [xfs]
xfs_refcount_find_shared+0x84/0xb0 [xfs]
xfs_getbmap+0x608/0x8c0 [xfs]
xfs_vn_fiemap+0xab/0xc0 [xfs]
do_vfs_ioctl+0x498/0x670
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x12/0x6f
CPU0
----
lock(&xfs_nondir_ilock_class);
<Interrupt>
lock(&xfs_nondir_ilock_class);
*** DEADLOCK ***
3 locks held by kswapd0/543:
stack backtrace:
CPU: 0 PID: 543 Comm: kswapd0 Tainted: G O 4.5.0-rc2+ #4
Call Trace:
lock_acquire+0xd8/0x1e0
down_write_nested+0x5e/0xc0
xfs_ilock+0x177/0x200 [xfs]
xfs_reflink_cancel_cow_range+0x150/0x300 [xfs]
xfs_fs_evict_inode+0xdc/0x1e0 [xfs]
evict+0xc5/0x190
dispose_list+0x39/0x60
prune_icache_sb+0x4b/0x60
super_cache_scan+0x14f/0x1a0
shrink_slab.part.63.constprop.79+0x1e9/0x4e0
shrink_zone+0x15e/0x170
kswapd+0x4f1/0xa80
kthread+0xf2/0x110
ret_from_fork+0x3f/0x70
To quote Dave:
"Ignoring whether reflink should be doing anything or not, that's a
"xfs_refcountbt_init_cursor() gets called both outside and inside
transactions" lockdep false positive case. The problem here is lockdep
has seen this allocation from within a transaction, hence a GFP_NOFS
allocation, and now it's seeing it in a GFP_KERNEL context. Also note
that we have an active reference to this inode.
So, because the reclaim annotations overload the interrupt level
detections and it's seen the inode ilock been taken in reclaim
("interrupt") context, this triggers a reclaim context warning where
it thinks it is unsafe to do this allocation in GFP_KERNEL context
holding the inode ilock..."
This sounds like a fundamental problem of the reclaim lock detection.
It is really impossible to annotate such a special usecase IMHO unless
the reclaim lockup detection is reworked completely. Until then it is
much better to provide a way to add "I know what I am doing flag" and
mark problematic places. This would prevent from abusing GFP_NOFS flag
which has a runtime effect even on configurations which have lockdep
disabled.
Introduce __GFP_NOLOCKDEP flag which tells the lockdep gfp tracking to
skip the current allocation request.
While we are at it also make sure that the radix tree doesn't
accidentaly override tags stored in the upper part of the gfp_mask.
Link: http://lkml.kernel.org/r/20170306131408.9828-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "scope GFP_NOFS api", v5.
This patch (of 7):
Commit 21caf2fc1931 ("mm: teach mm by current context info to not do I/O
during memory allocation") added the memalloc_noio_(save|restore)
functions to enable people to modify the MM behavior by disabling I/O
during memory allocation.
This was further extended in commit 934f3072c17c ("mm: clear __GFP_FS
when PF_MEMALLOC_NOIO is set").
memalloc_noio_* functions prevent allocation paths recursing back into
the filesystem without explicitly changing the flags for every
allocation site.
However, lockdep hasn't been keeping up with the changes and it entirely
misses handling the memalloc_noio adjustments. Instead, it is left to
the callers of __lockdep_trace_alloc to call the function after they
have shaven the respective GFP flags which can lead to false positives:
=================================
[ INFO: inconsistent lock state ]
4.10.0-nbor #134 Not tainted
---------------------------------
inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
fsstress/3365 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&xfs_nondir_ilock_class){++++?.}, at: xfs_ilock+0x141/0x230
{IN-RECLAIM_FS-W} state was registered at:
__lock_acquire+0x62a/0x17c0
lock_acquire+0xc5/0x220
down_write_nested+0x4f/0x90
xfs_ilock+0x141/0x230
xfs_reclaim_inode+0x12a/0x320
xfs_reclaim_inodes_ag+0x2c8/0x4e0
xfs_reclaim_inodes_nr+0x33/0x40
xfs_fs_free_cached_objects+0x19/0x20
super_cache_scan+0x191/0x1a0
shrink_slab+0x26f/0x5f0
shrink_node+0xf9/0x2f0
kswapd+0x356/0x920
kthread+0x10c/0x140
ret_from_fork+0x31/0x40
irq event stamp: 173777
hardirqs last enabled at (173777): __local_bh_enable_ip+0x70/0xc0
hardirqs last disabled at (173775): __local_bh_enable_ip+0x37/0xc0
softirqs last enabled at (173776): _xfs_buf_find+0x67a/0xb70
softirqs last disabled at (173774): _xfs_buf_find+0x5db/0xb70
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&xfs_nondir_ilock_class);
<Interrupt>
lock(&xfs_nondir_ilock_class);
*** DEADLOCK ***
4 locks held by fsstress/3365:
#0: (sb_writers#10){++++++}, at: mnt_want_write+0x24/0x50
#1: (&sb->s_type->i_mutex_key#12){++++++}, at: vfs_setxattr+0x6f/0xb0
#2: (sb_internal#2){++++++}, at: xfs_trans_alloc+0xfc/0x140
#3: (&xfs_nondir_ilock_class){++++?.}, at: xfs_ilock+0x141/0x230
stack backtrace:
CPU: 0 PID: 3365 Comm: fsstress Not tainted 4.10.0-nbor #134
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Call Trace:
kmem_cache_alloc_node_trace+0x3a/0x2c0
vm_map_ram+0x2a1/0x510
_xfs_buf_map_pages+0x77/0x140
xfs_buf_get_map+0x185/0x2a0
xfs_attr_rmtval_set+0x233/0x430
xfs_attr_leaf_addname+0x2d2/0x500
xfs_attr_set+0x214/0x420
xfs_xattr_set+0x59/0xb0
__vfs_setxattr+0x76/0xa0
__vfs_setxattr_noperm+0x5e/0xf0
vfs_setxattr+0xae/0xb0
setxattr+0x15e/0x1a0
path_setxattr+0x8f/0xc0
SyS_lsetxattr+0x11/0x20
entry_SYSCALL_64_fastpath+0x23/0xc6
Let's fix this by making lockdep explicitly do the shaving of respective
GFP flags.
Fixes: 934f3072c17c ("mm: clear __GFP_FS when PF_MEMALLOC_NOIO is set")
Link: http://lkml.kernel.org/r/20170306131408.9828-2-mhocko@kernel.org
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull audit updates from Paul Moore:
"Fourteen audit patches for v4.12 that span the full range of fixes,
new features, and internal cleanups.
We have a patches to move to 64-bit timestamps, convert refcounts from
atomic_t to refcount_t, track PIDs using the pid struct instead of
pid_t, convert our own private audit buffer cache to a standard
kmem_cache, log kernel module names when they are unloaded, and
normalize the NETFILTER_PKT to make the userspace folks happier.
From a fixes perspective, the most important is likely the auditd
connection tracking RCU fix; it was a rather brain dead bug that I'll
take the blame for, but thankfully it didn't seem to affect many
people (only one report).
I think the patch subject lines and commit descriptions do a pretty
good job of explaining the details and why the changes are important
so I'll point you there instead of duplicating it here; as usual, if
you have any questions you know where to find us.
We also manage to take out more code than we put in this time, that
always makes me happy :)"
* 'stable-4.12' of git://git.infradead.org/users/pcmoore/audit:
audit: fix the RCU locking for the auditd_connection structure
audit: use kmem_cache to manage the audit_buffer cache
audit: Use timespec64 to represent audit timestamps
audit: store the auditd PID as a pid struct instead of pid_t
audit: kernel generated netlink traffic should have a portid of 0
audit: combine audit_receive() and audit_receive_skb()
audit: convert audit_watch.count from atomic_t to refcount_t
audit: convert audit_tree.count from atomic_t to refcount_t
audit: normalize NETFILTER_PKT
netfilter: use consistent ipv4 network offset in xt_AUDIT
audit: log module name on delete_module
audit: remove unnecessary semicolon in audit_watch_handle_event()
audit: remove unnecessary semicolon in audit_mark_handle_event()
audit: remove unnecessary semicolon in audit_field_valid()
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Cong Wang correctly pointed out that the RCU read locking of the
auditd_connection struct was wrong, this patch correct this by
adopting a more traditional, and correct RCU locking model.
This patch is heavily based on an earlier prototype by Cong Wang.
Cc: <stable@vger.kernel.org> # 4.11.x-
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The audit subsystem implemented its own buffer cache mechanism which
is a bit silly these days when we could use the kmem_cache construct.
Some credit is due to Florian Westphal for originally proposing that
we remove the audit cache implementation in favor of simple
kmalloc()/kfree() calls, but I would rather have a dedicated slab
cache to ease debugging and future stats/performance work.
Cc: Florian Westphal <fw@strlen.de>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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struct timespec is not y2038 safe.
Audit timestamps are recorded in string format into
an audit buffer for a given context.
These mark the entry timestamps for the syscalls.
Use y2038 safe struct timespec64 to represent the times.
The log strings can handle this transition as strings can
hold upto 1024 characters.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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This is arguably the right thing to do, and will make it easier when
we start supporting multiple audit daemons in different namespaces.
Signed-off-by: Paul Moore <paul@paul-moore.com>
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We were setting the portid incorrectly in the netlink message headers,
fix that to always be 0 (nlmsg_pid = 0).
Signed-off-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
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There is no reason to have both of these functions, combine the two.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
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refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
[PM: fix subject line, add #include]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
[PM: fix subject line, add #include]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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When a sysadmin wishes to monitor module unloading with a syscall rule such as:
-a always,exit -F arch=x86_64 -S delete_module -F key=mod-unload
the SYSCALL record doesn't tell us what module was requested for unloading.
Use the new KERN_MODULE auxiliary record to record it.
The SYSCALL record result code will list the return code.
See: https://github.com/linux-audit/audit-kernel/issues/37
https://github.com/linux-audit/audit-kernel/issues/7
https://github.com/linux-audit/audit-kernel/wiki/RFE-Module-Load-Record-Format
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The excess ; after the closing parenthesis is just code-noise it has no
and can be removed.
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
[PM: tweaked subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The excess ; after the closing parenthesis is just code-noise it has no
and can be removed.
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
[PM: tweaked subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The excess ; after the closing parenthesis is just code-noise it has no
and can be removed.
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
[PM: tweak subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull security subsystem updates from James Morris:
"Highlights:
IMA:
- provide ">" and "<" operators for fowner/uid/euid rules
KEYS:
- add a system blacklist keyring
- add KEYCTL_RESTRICT_KEYRING, exposes keyring link restriction
functionality to userland via keyctl()
LSM:
- harden LSM API with __ro_after_init
- add prlmit security hook, implement for SELinux
- revive security_task_alloc hook
TPM:
- implement contextual TPM command 'spaces'"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (98 commits)
tpm: Fix reference count to main device
tpm_tis: convert to using locality callbacks
tpm: fix handling of the TPM 2.0 event logs
tpm_crb: remove a cruft constant
keys: select CONFIG_CRYPTO when selecting DH / KDF
apparmor: Make path_max parameter readonly
apparmor: fix parameters so that the permission test is bypassed at boot
apparmor: fix invalid reference to index variable of iterator line 836
apparmor: use SHASH_DESC_ON_STACK
security/apparmor/lsm.c: set debug messages
apparmor: fix boolreturn.cocci warnings
Smack: Use GFP_KERNEL for smk_netlbl_mls().
smack: fix double free in smack_parse_opts_str()
KEYS: add SP800-56A KDF support for DH
KEYS: Keyring asymmetric key restrict method with chaining
KEYS: Restrict asymmetric key linkage using a specific keychain
KEYS: Add a lookup_restriction function for the asymmetric key type
KEYS: Add KEYCTL_RESTRICT_KEYRING
KEYS: Consistent ordering for __key_link_begin and restrict check
KEYS: Add an optional lookup_restriction hook to key_type
...
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blob.
We switched from "struct task_struct"->security to "struct cred"->security
in Linux 2.6.29. But not all LSM modules were happy with that change.
TOMOYO LSM module is an example which want to use per "struct task_struct"
security blob, for TOMOYO's security context is defined based on "struct
task_struct" rather than "struct cred". AppArmor LSM module is another
example which want to use it, for AppArmor is currently abusing the cred
a little bit to store the change_hat and setexeccon info. Although
security_task_free() hook was revived in Linux 3.4 because Yama LSM module
wanted to release per "struct task_struct" security blob,
security_task_alloc() hook and "struct task_struct"->security field were
not revived. Nowadays, we are getting proposals of lightweight LSM modules
which want to use per "struct task_struct" security blob.
We are already allowing multiple concurrent LSM modules (up to one fully
armored module which uses "struct cred"->security field or exclusive hooks
like security_xfrm_state_pol_flow_match(), plus unlimited number of
lightweight modules which do not use "struct cred"->security nor exclusive
hooks) as long as they are built into the kernel. But this patch does not
implement variable length "struct task_struct"->security field which will
become needed when multiple LSM modules want to use "struct task_struct"->
security field. Although it won't be difficult to implement variable length
"struct task_struct"->security field, let's think about it after we merged
this patch.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Tested-by: Djalal Harouni <tixxdz@gmail.com>
Acked-by: José Bollo <jobol@nonadev.net>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: James Morris <james.l.morris@oracle.com>
Cc: José Bollo <jobol@nonadev.net>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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When SELinux was first added to the kernel, a process could only get
and set its own resource limits via getrlimit(2) and setrlimit(2), so no
MAC checks were required for those operations, and thus no security hooks
were defined for them. Later, SELinux introduced a hook for setlimit(2)
with a check if the hard limit was being changed in order to be able to
rely on the hard limit value as a safe reset point upon context
transitions.
Later on, when prlimit(2) was added to the kernel with the ability to get
or set resource limits (hard or soft) of another process, LSM/SELinux was
not updated other than to pass the target process to the setrlimit hook.
This resulted in incomplete control over both getting and setting the
resource limits of another process.
Add a new security_task_prlimit() hook to the check_prlimit_permission()
function to provide complete mediation. The hook is only called when
acting on another task, and only if the existing DAC/capability checks
would allow access. Pass flags down to the hook to indicate whether the
prlimit(2) call will read, write, or both read and write the resource
limits of the target process.
The existing security_task_setrlimit() hook is left alone; it continues
to serve a purpose in supporting the ability to make decisions based on
the old and/or new resource limit values when setting limits. This
is consistent with the DAC/capability logic, where
check_prlimit_permission() performs generic DAC/capability checks for
acting on another task, while do_prlimit() performs a capability check
based on a comparison of the old and new resource limits. Fix the
inline documentation for the hook to match the code.
Implement the new hook for SELinux. For setting resource limits, we
reuse the existing setrlimit permission. Note that this does overload
the setrlimit permission to mean the ability to set the resource limit
(soft or hard) of another process or the ability to change one's own
hard limit. For getting resource limits, a new getrlimit permission
is defined. This was not originally defined since getrlimit(2) could
only be used to obtain a process' own limits.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
tty: fix comment for __tty_alloc_driver()
init/main: properly align the multi-line comment
init/main: Fix double "the" in comment
Fix dead URLs to ftp.kernel.org
drivers: Clean up duplicated email address
treewide: Fix typo in xml/driver-api/basics.xml
tools/testing/selftests/powerpc: remove redundant CFLAGS in Makefile: "-Wall -O2 -Wall" -> "-O2 -Wall"
selftests/timers: Spelling s/privledges/privileges/
HID: picoLCD: Spelling s/REPORT_WRTIE_MEMORY/REPORT_WRITE_MEMORY/
net: phy: dp83848: Fix Typo
UBI: Fix typos
Documentation: ftrace.txt: Correct nice value of 120 priority
net: fec: Fix typo in error msg and comment
treewide: Fix typos in printk
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This patch fix spelling typos found in
Documentation/output/xml/driver-api/basics.xml.
It is because the xml file was generated from comments in source,
so I had to fix the comments.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
Pull livepatch updates from Jiri Kosina:
- a per-task consistency model is being added for architectures that
support reliable stack dumping (extending this, currently rather
trivial set, is currently in the works).
This extends the nature of the types of patches that can be applied
by live patching infrastructure. The code stems from the design
proposal made [1] back in November 2014. It's a hybrid of SUSE's
kGraft and RH's kpatch, combining advantages of both: it uses
kGraft's per-task consistency and syscall barrier switching combined
with kpatch's stack trace switching. There are also a number of
fallback options which make it quite flexible.
Most of the heavy lifting done by Josh Poimboeuf with help from
Miroslav Benes and Petr Mladek
[1] https://lkml.kernel.org/r/20141107140458.GA21774@suse.cz
- module load time patch optimization from Zhou Chengming
- a few assorted small fixes
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
livepatch: add missing printk newlines
livepatch: Cancel transition a safe way for immediate patches
livepatch: Reduce the time of finding module symbols
livepatch: make klp_mutex proper part of API
livepatch: allow removal of a disabled patch
livepatch: add /proc/<pid>/patch_state
livepatch: change to a per-task consistency model
livepatch: store function sizes
livepatch: use kstrtobool() in enabled_store()
livepatch: move patching functions into patch.c
livepatch: remove unnecessary object loaded check
livepatch: separate enabled and patched states
livepatch/s390: add TIF_PATCH_PENDING thread flag
livepatch/s390: reorganize TIF thread flag bits
livepatch/powerpc: add TIF_PATCH_PENDING thread flag
livepatch/x86: add TIF_PATCH_PENDING thread flag
livepatch: create temporary klp_update_patch_state() stub
x86/entry: define _TIF_ALLWORK_MASK flags explicitly
stacktrace/x86: add function for detecting reliable stack traces
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'for-4.12/klp-hybrid-consistency-model' into for-linus
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klp_init_transition() does not set func->transition for immediate patches.
Then klp_ftrace_handler() could use the new code immediately. As a result,
it is not safe to put the livepatch module in klp_cancel_transition().
This patch reverts most of the last minute changes klp_cancel_transition().
It keeps the warning about a misuse because it still makes sense.
Fixes: 3ec24776bfd0 ("livepatch: allow removal of a disabled patch")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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klp_mutex is shared between core.c and transition.c, and as such would
rather be properly located in a header so that we don't have to play
'extern' games from .c sources.
This also silences sparse warning (wrongly) suggesting that klp_mutex
should be defined static.
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Currently we do not allow patch module to unload since there is no
method to determine if a task is still running in the patched code.
The consistency model gives us the way because when the unpatching
finishes we know that all tasks were marked as safe to call an original
function. Thus every new call to the function calls the original code
and at the same time no task can be somewhere in the patched code,
because it had to leave that code to be marked as safe.
We can safely let the patch module go after that.
Completion is used for synchronization between module removal and sysfs
infrastructure in a similar way to commit 942e443127e9 ("module: Fix
mod->mkobj.kobj potentially freed too early").
Note that we still do not allow the removal for immediate model, that is
no consistency model. The module refcount may increase in this case if
somebody disables and enables the patch several times. This should not
cause any harm.
With this change a call to try_module_get() is moved to
__klp_enable_patch from klp_register_patch to make module reference
counting symmetric (module_put() is in a patch disable path) and to
allow to take a new reference to a disabled module when being enabled.
Finally, we need to be very careful about possible races between
klp_unregister_patch(), kobject_put() functions and operations
on the related sysfs files.
kobject_put(&patch->kobj) must be called without klp_mutex. Otherwise,
it might be blocked by enabled_store() that needs the mutex as well.
In addition, enabled_store() must check if the patch was not
unregisted in the meantime.
There is no need to do the same for other kobject_put() callsites
at the moment. Their sysfs operations neither take the lock nor
they access any data that might be freed in the meantime.
There was an attempt to use kobjects the right way and prevent these
races by design. But it made the patch definition more complicated
and opened another can of worms. See
https://lkml.kernel.org/r/1464018848-4303-1-git-send-email-pmladek@suse.com
[Thanks to Petr Mladek for improving the commit message.]
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Change livepatch to use a basic per-task consistency model. This is the
foundation which will eventually enable us to patch those ~10% of
security patches which change function or data semantics. This is the
biggest remaining piece needed to make livepatch more generally useful.
This code stems from the design proposal made by Vojtech [1] in November
2014. It's a hybrid of kGraft and kpatch: it uses kGraft's per-task
consistency and syscall barrier switching combined with kpatch's stack
trace switching. There are also a number of fallback options which make
it quite flexible.
Patches are applied on a per-task basis, when the task is deemed safe to
switch over. When a patch is enabled, livepatch enters into a
transition state where tasks are converging to the patched state.
Usually this transition state can complete in a few seconds. The same
sequence occurs when a patch is disabled, except the tasks converge from
the patched state to the unpatched state.
An interrupt handler inherits the patched state of the task it
interrupts. The same is true for forked tasks: the child inherits the
patched state of the parent.
Livepatch uses several complementary approaches to determine when it's
safe to patch tasks:
1. The first and most effective approach is stack checking of sleeping
tasks. If no affected functions are on the stack of a given task,
the task is patched. In most cases this will patch most or all of
the tasks on the first try. Otherwise it'll keep trying
periodically. This option is only available if the architecture has
reliable stacks (HAVE_RELIABLE_STACKTRACE).
2. The second approach, if needed, is kernel exit switching. A
task is switched when it returns to user space from a system call, a
user space IRQ, or a signal. It's useful in the following cases:
a) Patching I/O-bound user tasks which are sleeping on an affected
function. In this case you have to send SIGSTOP and SIGCONT to
force it to exit the kernel and be patched.
b) Patching CPU-bound user tasks. If the task is highly CPU-bound
then it will get patched the next time it gets interrupted by an
IRQ.
c) In the future it could be useful for applying patches for
architectures which don't yet have HAVE_RELIABLE_STACKTRACE. In
this case you would have to signal most of the tasks on the
system. However this isn't supported yet because there's
currently no way to patch kthreads without
HAVE_RELIABLE_STACKTRACE.
3. For idle "swapper" tasks, since they don't ever exit the kernel, they
instead have a klp_update_patch_state() call in the idle loop which
allows them to be patched before the CPU enters the idle state.
(Note there's not yet such an approach for kthreads.)
All the above approaches may be skipped by setting the 'immediate' flag
in the 'klp_patch' struct, which will disable per-task consistency and
patch all tasks immediately. This can be useful if the patch doesn't
change any function or data semantics. Note that, even with this flag
set, it's possible that some tasks may still be running with an old
version of the function, until that function returns.
There's also an 'immediate' flag in the 'klp_func' struct which allows
you to specify that certain functions in the patch can be applied
without per-task consistency. This might be useful if you want to patch
a common function like schedule(), and the function change doesn't need
consistency but the rest of the patch does.
For architectures which don't have HAVE_RELIABLE_STACKTRACE, the user
must set patch->immediate which causes all tasks to be patched
immediately. This option should be used with care, only when the patch
doesn't change any function or data semantics.
In the future, architectures which don't have HAVE_RELIABLE_STACKTRACE
may be allowed to use per-task consistency if we can come up with
another way to patch kthreads.
The /sys/kernel/livepatch/<patch>/transition file shows whether a patch
is in transition. Only a single patch (the topmost patch on the stack)
can be in transition at a given time. A patch can remain in transition
indefinitely, if any of the tasks are stuck in the initial patch state.
A transition can be reversed and effectively canceled by writing the
opposite value to the /sys/kernel/livepatch/<patch>/enabled file while
the transition is in progress. Then all the tasks will attempt to
converge back to the original patch state.
[1] https://lkml.kernel.org/r/20141107140458.GA21774@suse.cz
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Ingo Molnar <mingo@kernel.org> # for the scheduler changes
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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For the consistency model we'll need to know the sizes of the old and
new functions to determine if they're on the stacks of any tasks.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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The sysfs enabled value is a boolean, so kstrtobool() is a better fit
for parsing the input string since it does the range checking for us.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Move functions related to the actual patching of functions and objects
into a new patch.c file.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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klp_patch_object()'s callers already ensure that the object is loaded,
so its call to klp_is_object_loaded() is unnecessary.
This will also make it possible to move the patching code into a
separate file.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Once we have a consistency model, patches and their objects will be
enabled and disabled at different times. For example, when a patch is
disabled, its loaded objects' funcs can remain registered with ftrace
indefinitely until the unpatching operation is complete and they're no
longer in use.
It's less confusing if we give them different names: patches can be
enabled or disabled; objects (and their funcs) can be patched or
unpatched:
- Enabled means that a patch is logically enabled (but not necessarily
fully applied).
- Patched means that an object's funcs are registered with ftrace and
added to the klp_ops func stack.
Also, since these states are binary, represent them with booleans
instead of ints.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Create temporary stubs for klp_update_patch_state() so we can add
TIF_PATCH_PENDING to different architectures in separate patches without
breaking build bisectability.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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For live patching and possibly other use cases, a stack trace is only
useful if it can be assured that it's completely reliable. Add a new
save_stack_trace_tsk_reliable() function to achieve that.
Note that if the target task isn't the current task, and the target task
is allowed to run, then it could be writing the stack while the unwinder
is reading it, resulting in possible corruption. So the caller of
save_stack_trace_tsk_reliable() must ensure that the task is either
'current' or inactive.
save_stack_trace_tsk_reliable() relies on the x86 unwinder's detection
of pt_regs on the stack. If the pt_regs are not user-mode registers
from a syscall, then they indicate an in-kernel interrupt or exception
(e.g. preemption or a page fault), in which case the stack is considered
unreliable due to the nature of frame pointers.
It also relies on the x86 unwinder's detection of other issues, such as:
- corrupted stack data
- stack grows the wrong way
- stack walk doesn't reach the bottom
- user didn't provide a large enough entries array
Such issues are reported by checking unwind_error() and !unwind_done().
Also add CONFIG_HAVE_RELIABLE_STACKTRACE so arch-independent code can
determine at build time whether the function is implemented.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Ingo Molnar <mingo@kernel.org> # for the x86 changes
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Add missing newlines to some pr_err() strings.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Jessica Yu <jeyu@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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It's reported that the time of insmoding a klp.ko for one of our
out-tree modules is too long.
~ time sudo insmod klp.ko
real 0m23.799s
user 0m0.036s
sys 0m21.256s
Then we found the reason: our out-tree module used a lot of static local
variables, so klp.ko has a lot of relocation records which reference the
module. Then for each such entry klp_find_object_symbol() is called to
resolve it, but this function uses the interface kallsyms_on_each_symbol()
even for finding module symbols, so will waste a lot of time on walking
through vmlinux kallsyms table many times.
This patch changes it to use module_kallsyms_on_each_symbol() for modules
symbols. After we apply this patch, the sys time reduced dramatically.
~ time sudo insmod klp.ko
real 0m1.007s
user 0m0.032s
sys 0m0.924s
Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Pull networking updates from David Millar:
"Here are some highlights from the 2065 networking commits that
happened this development cycle:
1) XDP support for IXGBE (John Fastabend) and thunderx (Sunil Kowuri)
2) Add a generic XDP driver, so that anyone can test XDP even if they
lack a networking device whose driver has explicit XDP support
(me).
3) Sparc64 now has an eBPF JIT too (me)
4) Add a BPF program testing framework via BPF_PROG_TEST_RUN (Alexei
Starovoitov)
5) Make netfitler network namespace teardown less expensive (Florian
Westphal)
6) Add symmetric hashing support to nft_hash (Laura Garcia Liebana)
7) Implement NAPI and GRO in netvsc driver (Stephen Hemminger)
8) Support TC flower offload statistics in mlxsw (Arkadi Sharshevsky)
9) Multiqueue support in stmmac driver (Joao Pinto)
10) Remove TCP timewait recycling, it never really could possibly work
well in the real world and timestamp randomization really zaps any
hint of usability this feature had (Soheil Hassas Yeganeh)
11) Support level3 vs level4 ECMP route hashing in ipv4 (Nikolay
Aleksandrov)
12) Add socket busy poll support to epoll (Sridhar Samudrala)
13) Netlink extended ACK support (Johannes Berg, Pablo Neira Ayuso,
and several others)
14) IPSEC hw offload infrastructure (Steffen Klassert)"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (2065 commits)
tipc: refactor function tipc_sk_recv_stream()
tipc: refactor function tipc_sk_recvmsg()
net: thunderx: Optimize page recycling for XDP
net: thunderx: Support for XDP header adjustment
net: thunderx: Add support for XDP_TX
net: thunderx: Add support for XDP_DROP
net: thunderx: Add basic XDP support
net: thunderx: Cleanup receive buffer allocation
net: thunderx: Optimize CQE_TX handling
net: thunderx: Optimize RBDR descriptor handling
net: thunderx: Support for page recycling
ipx: call ipxitf_put() in ioctl error path
net: sched: add helpers to handle extended actions
qed*: Fix issues in the ptp filter config implementation.
qede: Fix concurrency issue in PTP Tx path processing.
stmmac: Add support for SIMATIC IOT2000 platform
net: hns: fix ethtool_get_strings overflow in hns driver
tcp: fix wraparound issue in tcp_lp
bpf, arm64: fix jit branch offset related to ldimm64
bpf, arm64: implement jiting of BPF_XADD
...
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llvm 4.0 and above generates the code like below:
....
440: (b7) r1 = 15
441: (05) goto pc+73
515: (79) r6 = *(u64 *)(r10 -152)
516: (bf) r7 = r10
517: (07) r7 += -112
518: (bf) r2 = r7
519: (0f) r2 += r1
520: (71) r1 = *(u8 *)(r8 +0)
521: (73) *(u8 *)(r2 +45) = r1
....
and the verifier complains "R2 invalid mem access 'inv'" for insn #521.
This is because verifier marks register r2 as unknown value after #519
where r2 is a stack pointer and r1 holds a constant value.
Teach verifier to recognize "stack_ptr + imm" and
"stack_ptr + reg with const val" as valid stack_ptr with new offset.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Hannes rightfully spotted that the bpf_lock doesn't need to be
irqsave variant. We never perform any such updates where this
would be necessary (neither right now nor in future), therefore
relax this further.
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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When iterating through a map, we need to find a key that does not exist
in the map so map_get_next_key will give us the first key of the map.
This often requires a lot of guessing in production systems.
This patch makes map_get_next_key return the first key when the key
pointer in the parameter is NULL.
Signed-off-by: Teng Qin <qinteng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Now that also the last in-tree user of the xdp_adjust_head bit has
been removed, we can remove the flag from struct bpf_prog altogether.
This, at the same time, also makes sure that any future driver for
XDP comes with bpf_xdp_adjust_head() support right away.
A rejection based on this flag would also mean that tail calls
couldn't be used with such driver as per c2002f983767 ("bpf: fix
checking xdp_adjust_head on tail calls") fix, thus lets not allow
for it in the first place.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Both conflict were simple overlapping changes.
In the kaweth case, Eric Dumazet's skb_cow() bug fix overlapped the
conversion of the driver in net-next to use in-netdev stats.
Signed-off-by: David S. Miller <davem@davemloft.net>
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We are not supposed to add new entries to this thing
any more.
Thanks to Eric Dumazet for noticing this.
Signed-off-by: David S. Miller <davem@davemloft.net>
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Constants used for tuning are generally a bad idea, especially as hardware
changes over time. Replace the constant 2 jiffies with sysctl variable
netdev_budget_usecs to enable sysadmins to tune the softirq processing.
Also document the variable.
For example, a very fast machine might tune this to 1000 microseconds,
while my regression testing 486DX-25 needs it to be 4000 microseconds on
a nearly idle network to prevent time_squeeze from being incremented.
Version 2: changed jiffies to microseconds for predictable units.
Signed-off-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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A function in kernel/bpf/syscall.c which got a bug fix in 'net'
was moved to kernel/bpf/verifier.c in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
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After doing map_perf_test with a much bigger
BPF_F_NO_COMMON_LRU map, the perf report shows a
lot of time spent in rotating the inactive list (i.e.
__bpf_lru_list_rotate_inactive):
> map_perf_test 32 8 10000 1000000 | awk '{sum += $3}END{print sum}'
19644783 (19M/s)
> map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}'
6283930 (6.28M/s)
By inactive, it usually means the element is not in cache. Hence,
there is a need to tune the PERCPU_NR_SCANS value.
This patch finds a better number of elements to
scan during each list rotation. The PERCPU_NR_SCANS (which
is defined the same as PERCPU_FREE_TARGET) decreases
from 16 elements to 4 elements. This change only
affects the BPF_F_NO_COMMON_LRU map.
The test_lru_dist does not show meaningful difference
between 16 and 4. Our production L4 load balancer which uses
the LRU map for conntrack-ing also shows little change in cache
hit rate. Since both benchmark and production data show no
cache-hit difference, PERCPU_NR_SCANS is lowered from 16 to 4.
We can consider making it configurable if we find a usecase
later that shows another value works better and/or use
a different rotation strategy.
After this change:
> map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}'
9240324 (9.2M/s)
i.e. 6.28M/s -> 9.2M/s
The test_lru_dist has not shown meaningful difference:
> test_lru_dist zipf.100k.a1_01.out 4000 1:
nr_misses: 31575 (Before) vs 31566 (After)
> test_lru_dist zipf.100k.a0_01.out 40000 1
nr_misses: 67036 (Before) vs 67031 (After)
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Conflicts were simply overlapping changes. In the net/ipv4/route.c
case the code had simply moved around a little bit and the same fix
was made in both 'net' and 'net-next'.
In the net/sched/sch_generic.c case a fix in 'net' happened at
the same time that a new argument was added to qdisc_hash_add().
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add the base infrastructure and UAPI for netlink extended ACK
reporting. All "manual" calls to netlink_ack() pass NULL for now and
thus don't get extended ACK reporting.
Big thanks goes to Pablo Neira Ayuso for not only bringing up the
whole topic at netconf (again) but also coming up with the nlattr
passing trick and various other ideas.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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