The patch titled
Subject: slab: do not panic on invalid gfp_mask
has been added to the -mm tree. Its filename is
slab-do-not-panic-on-invalid-gfp_mask.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/slab-do-not-panic-on-invalid-gfp_mask.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/slab-do-not-panic-on-invalid-gfp_mask.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: 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.
[ 31.914753] Unexpected gfp: 0x2 (__GFP_HIGHMEM). Fixing up to gfp: 0x24000c0 (GFP_KERNEL). Fix your code!
[ 31.914754] CPU: 0 PID: 2916 Comm: insmod Tainted: G O 4.6.0-slabgfp2-00002-g4cdfc2ef4892-dirty #936
[ 31.914755] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[ 31.914756] 0000000000000000 ffff88000d777c00 ffffffff8130e2fb ffff88000ec006c0
[ 31.914758] 000000000000000c ffff88000d777c58 ffffffff811791dd 0000000000000246
[ 31.914759] 0000000000000246 0000000000000046 00000002024000c0 ffff88000fa1d888
[ 31.914759] Call Trace:
[ 31.914760] [<ffffffff8130e2fb>] dump_stack+0x67/0x90
[ 31.914762] [<ffffffff811791dd>] cache_alloc_refill+0x201/0x617
[ 31.914763] [<ffffffff81179b3f>] kmem_cache_alloc_trace+0xa7/0x24a
[ 31.914764] [<ffffffffa0005000>] ? 0xffffffffa0005000
[ 31.914765] [<ffffffffa0005020>] mymodule_init+0x20/0x1000 [test_slab]
[ 31.914767] [<ffffffff81000402>] do_one_initcall+0xe7/0x16c
[ 31.914768] [<ffffffff810b02de>] ? rcu_read_lock_sched_held+0x61/0x69
[ 31.914769] [<ffffffff81179c2f>] ? kmem_cache_alloc_trace+0x197/0x24a
[ 31.914771] [<ffffffff81125edc>] do_init_module+0x5f/0x1d9
[ 31.914772] [<ffffffff810d2c66>] load_module+0x1a3d/0x1f21
[ 31.914774] [<ffffffff81622931>] ? retint_kernel+0x2d/0x2d
[ 31.914775] [<ffffffff810d3232>] SyS_init_module+0xe8/0x10e
[ 31.914776] [<ffffffff810d3232>] ? SyS_init_module+0xe8/0x10e
[ 31.914778] [<ffffffff81001d08>] do_syscall_64+0x68/0x13f
[ 31.914779] [<ffffffff8162201a>] entry_SYSCALL64_slow_path+0x25/0x25
Link: http://lkml.kernel.org/r/1465548200-11384-2-git-send-email-mhocko@xxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 6 ++++--
mm/slub.c | 5 +++--
2 files changed, 7 insertions(+), 4 deletions(-)
diff -puN mm/slab.c~slab-do-not-panic-on-invalid-gfp_mask mm/slab.c
--- a/mm/slab.c~slab-do-not-panic-on-invalid-gfp_mask
+++ a/mm/slab.c
@@ -2687,8 +2687,10 @@ static struct page *cache_grow_begin(str
*/
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 -puN mm/slub.c~slab-do-not-panic-on-invalid-gfp_mask mm/slub.c
--- a/mm/slub.c~slab-do-not-panic-on-invalid-gfp_mask
+++ a/mm/slub.c
@@ -1613,8 +1613,9 @@ static struct page *new_slab(struct kmem
{
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,
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
tree-wide-get-rid-of-__gfp_repeat-for-order-0-allocations-part-i.patch
x86-get-rid-of-superfluous-__gfp_repeat.patch
x86-efi-get-rid-of-superfluous-__gfp_repeat.patch
arm64-get-rid-of-superfluous-__gfp_repeat.patch
arc-get-rid-of-superfluous-__gfp_repeat.patch
mips-get-rid-of-superfluous-__gfp_repeat.patch
nios2-get-rid-of-superfluous-__gfp_repeat.patch
parisc-get-rid-of-superfluous-__gfp_repeat.patch
score-get-rid-of-superfluous-__gfp_repeat.patch
powerpc-get-rid-of-superfluous-__gfp_repeat.patch
sparc-get-rid-of-superfluous-__gfp_repeat.patch
s390-get-rid-of-superfluous-__gfp_repeat.patch
sh-get-rid-of-superfluous-__gfp_repeat.patch
tile-get-rid-of-superfluous-__gfp_repeat.patch
unicore32-get-rid-of-superfluous-__gfp_repeat.patch
jbd2-get-rid-of-superfluous-__gfp_repeat.patch
arm-get-rid-of-superfluous-__gfp_repeat.patch
slab-make-gfp_slab_bug_mask-information-more-human-readable.patch
slab-do-not-panic-on-invalid-gfp_mask.patch
mm-oom_reaper-make-sure-that-mmput_async-is-called-only-when-memory-was-reaped.patch
mm-memcg-use-consistent-gfp-flags-during-readahead.patch
mm-memcg-use-consistent-gfp-flags-during-readahead-fix.patch
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