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authorMichal Hocko <mhocko@suse.com>2016-07-27 00:22:05 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 01:19:19 +0200
commit72baeef0c2710a9ac99670e59d4865b24ffd2d18 (patch)
treea346826e2def84b45d0a15d1e59953665fd4ac42 /mm
parentslab: make GFP_SLAB_BUG_MASK information more human readable (diff)
downloadlinux-72baeef0c2710a9ac99670e59d4865b24ffd2d18.tar.xz
linux-72baeef0c2710a9ac99670e59d4865b24ffd2d18.zip
slab: do not panic on invalid gfp_mask
Both SLAB and SLUB BUG() when a caller provides an invalid gfp_mask. This is a rather harsh way to announce a non-critical issue. Allocator is free to ignore invalid flags. Let's simply replace BUG() by dump_stack to tell the offender and fixup the mask to move on with the allocation request. This is an example for kmalloc(GFP_KERNEL|__GFP_HIGHMEM) from a test module: Unexpected gfp: 0x2 (__GFP_HIGHMEM). Fixing up to gfp: 0x24000c0 (GFP_KERNEL). Fix your code! CPU: 0 PID: 2916 Comm: insmod Tainted: G O 4.6.0-slabgfp2-00002-g4cdfc2ef4892-dirty #936 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 Call Trace: dump_stack+0x67/0x90 cache_alloc_refill+0x201/0x617 kmem_cache_alloc_trace+0xa7/0x24a ? 0xffffffffa0005000 mymodule_init+0x20/0x1000 [test_slab] do_one_initcall+0xe7/0x16c ? rcu_read_lock_sched_held+0x61/0x69 ? kmem_cache_alloc_trace+0x197/0x24a do_init_module+0x5f/0x1d9 load_module+0x1a3d/0x1f21 ? retint_kernel+0x2d/0x2d SyS_init_module+0xe8/0x10e ? SyS_init_module+0xe8/0x10e do_syscall_64+0x68/0x13f entry_SYSCALL64_slow_path+0x25/0x25 Link: http://lkml.kernel.org/r/1465548200-11384-2-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/slab.c6
-rw-r--r--mm/slub.c5
2 files changed, 7 insertions, 4 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 03fb724d6e48..fc9496bdd038 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2687,8 +2687,10 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
*/
if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
- pr_emerg("Unexpected gfp: %#x (%pGg)\n", invalid_mask, &invalid_mask);
- BUG();
+ flags &= ~GFP_SLAB_BUG_MASK;
+ pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
+ invalid_mask, &invalid_mask, flags, &flags);
+ dump_stack();
}
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
diff --git a/mm/slub.c b/mm/slub.c
index a2fe4edc3599..c0cfa2722539 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1613,8 +1613,9 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
{
if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
- pr_emerg("Unexpected gfp: %#x (%pGg)\n", invalid_mask, &invalid_mask);
- BUG();
+ flags &= ~GFP_SLAB_BUG_MASK;
+ pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
+ invalid_mask, &invalid_mask, flags, &flags);
}
return allocate_slab(s,