Revision e009d5dc0a94a7133e5f1c083732d760bfd038e6 authored by Michal Hocko on 12 March 2015, 23:25:52 UTC, committed by Linus Torvalds on 13 March 2015, 01:46:07 UTC
Tetsuo Handa has pointed out that __GFP_NOFAIL allocations might fail after OOM killer is disabled if the allocation is performed by a kernel thread. This behavior was introduced from the very beginning by 7f33d49a2ed5 ("mm, PM/Freezer: Disable OOM killer when tasks are frozen"). This means that the basic contract for the allocation request is broken and the context requesting such an allocation might blow up unexpectedly. There are basically two ways forward. 1) move oom_killer_disable after kernel threads are frozen. This has a risk that the OOM victim wouldn't be able to finish because it would depend on an already frozen kernel thread. This would be really tricky to debug. 2) do not fail GFP_NOFAIL allocation no matter what and risk a potential Freezable kernel threads will loop and fail the suspend. Incidental allocations after kernel threads are frozen will at least dump a warning - if we are lucky and the serial console is still active of course... This patch implements the later option because it is safer. We would see warning rather than allocation failures for the kernel threads which would blow up otherwise and have a higher chances to identify __GFP_NOFAIL users from deeper pm code. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: David Rientjes <rientjes@gooogle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 8792f77
File | Mode | Size |
---|---|---|
tests | ||
Kconfig | -rw-r--r-- | 2.9 KB |
Makefile | -rw-r--r-- | 880 bytes |
acl.c | -rw-r--r-- | 3.7 KB |
async-thread.c | -rw-r--r-- | 9.1 KB |
async-thread.h | -rw-r--r-- | 2.8 KB |
backref.c | -rw-r--r-- | 49.9 KB |
backref.h | -rw-r--r-- | 2.7 KB |
btrfs_inode.h | -rw-r--r-- | 8.4 KB |
check-integrity.c | -rw-r--r-- | 98.2 KB |
check-integrity.h | -rw-r--r-- | 1.3 KB |
compression.c | -rw-r--r-- | 28.2 KB |
compression.h | -rw-r--r-- | 2.8 KB |
ctree.c | -rw-r--r-- | 151.6 KB |
ctree.h | -rw-r--r-- | 134.6 KB |
delayed-inode.c | -rw-r--r-- | 51.8 KB |
delayed-inode.h | -rw-r--r-- | 4.8 KB |
delayed-ref.c | -rw-r--r-- | 25.4 KB |
delayed-ref.h | -rw-r--r-- | 7.7 KB |
dev-replace.c | -rw-r--r-- | 29.2 KB |
dev-replace.h | -rw-r--r-- | 1.8 KB |
dir-item.c | -rw-r--r-- | 12.8 KB |
disk-io.c | -rw-r--r-- | 117.0 KB |
disk-io.h | -rw-r--r-- | 5.6 KB |
export.c | -rw-r--r-- | 7.5 KB |
export.h | -rw-r--r-- | 301 bytes |
extent-tree.c | -rw-r--r-- | 261.6 KB |
extent_io.c | -rw-r--r-- | 140.1 KB |
extent_io.h | -rw-r--r-- | 14.2 KB |
extent_map.c | -rw-r--r-- | 11.6 KB |
extent_map.h | -rw-r--r-- | 2.4 KB |
file-item.c | -rw-r--r-- | 25.8 KB |
file.c | -rw-r--r-- | 76.1 KB |
free-space-cache.c | -rw-r--r-- | 87.0 KB |
free-space-cache.h | -rw-r--r-- | 4.6 KB |
hash.c | -rw-r--r-- | 1.0 KB |
hash.h | -rw-r--r-- | 1.2 KB |
inode-item.c | -rw-r--r-- | 11.7 KB |
inode-map.c | -rw-r--r-- | 14.2 KB |
inode-map.h | -rw-r--r-- | 455 bytes |
inode.c | -rw-r--r-- | 254.1 KB |
ioctl.c | -rw-r--r-- | 128.1 KB |
locking.c | -rw-r--r-- | 8.0 KB |
locking.h | -rw-r--r-- | 2.1 KB |
lzo.c | -rw-r--r-- | 10.3 KB |
math.h | -rw-r--r-- | 1.1 KB |
ordered-data.c | -rw-r--r-- | 28.2 KB |
ordered-data.h | -rw-r--r-- | 6.8 KB |
orphan.c | -rw-r--r-- | 1.7 KB |
print-tree.c | -rw-r--r-- | 10.6 KB |
print-tree.h | -rw-r--r-- | 906 bytes |
props.c | -rw-r--r-- | 9.7 KB |
props.h | -rw-r--r-- | 1.3 KB |
qgroup.c | -rw-r--r-- | 70.7 KB |
qgroup.h | -rw-r--r-- | 4.3 KB |
raid56.c | -rw-r--r-- | 64.7 KB |
raid56.h | -rw-r--r-- | 2.1 KB |
rcu-string.h | -rw-r--r-- | 1.5 KB |
reada.c | -rw-r--r-- | 24.5 KB |
relocation.c | -rw-r--r-- | 109.4 KB |
root-tree.c | -rw-r--r-- | 12.6 KB |
scrub.c | -rw-r--r-- | 110.1 KB |
send.c | -rw-r--r-- | 138.8 KB |
send.h | -rw-r--r-- | 2.9 KB |
struct-funcs.c | -rw-r--r-- | 4.5 KB |
super.c | -rw-r--r-- | 56.4 KB |
sysfs.c | -rw-r--r-- | 19.4 KB |
sysfs.h | -rw-r--r-- | 2.6 KB |
transaction.c | -rw-r--r-- | 59.1 KB |
transaction.h | -rw-r--r-- | 6.0 KB |
tree-defrag.c | -rw-r--r-- | 3.3 KB |
tree-log.c | -rw-r--r-- | 123.6 KB |
tree-log.h | -rw-r--r-- | 2.8 KB |
ulist.c | -rw-r--r-- | 6.2 KB |
ulist.h | -rw-r--r-- | 2.0 KB |
uuid-tree.c | -rw-r--r-- | 8.0 KB |
volumes.c | -rw-r--r-- | 172.8 KB |
volumes.h | -rw-r--r-- | 15.5 KB |
xattr.c | -rw-r--r-- | 13.0 KB |
xattr.h | -rw-r--r-- | 1.5 KB |
zlib.c | -rw-r--r-- | 10.5 KB |
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...