Revision 6f6acb00514c10be35529402f36ad7a288f08c2e authored by Michal Hocko on 22 May 2014, 18:54:19 UTC, committed by Linus Torvalds on 23 May 2014, 16:37:29 UTC
Commit 284f39afeaa4 ("mm: memcg: push !mm handling out to page cache charge function") explicitly checks for page cache charges without any mm context (from kernel thread context[1]). This seemed to be the only possible case where memory could be charged without mm context so commit 03583f1a631c ("memcg: remove unnecessary !mm check from try_get_mem_cgroup_from_mm()") removed the mm check from get_mem_cgroup_from_mm(). This however caused another NULL ptr dereference during early boot when loopback kernel thread splices to tmpfs as reported by Stephan Kulow: BUG: unable to handle kernel NULL pointer dereference at 0000000000000360 IP: get_mem_cgroup_from_mm.isra.42+0x2b/0x60 Oops: 0000 [#1] SMP Modules linked in: btrfs dm_multipath dm_mod scsi_dh multipath raid10 raid456 async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx raid1 raid0 md_mod parport_pc parport nls_utf8 isofs usb_storage iscsi_ibft iscsi_boot_sysfs arc4 ecb fan thermal nfs lockd fscache nls_iso8859_1 nls_cp437 sg st hid_generic usbhid af_packet sunrpc sr_mod cdrom ata_generic uhci_hcd virtio_net virtio_blk ehci_hcd usbcore ata_piix floppy processor button usb_common virtio_pci virtio_ring virtio edd squashfs loop ppa] CPU: 0 PID: 97 Comm: loop1 Not tainted 3.15.0-rc5-5-default #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: __mem_cgroup_try_charge_swapin+0x40/0xe0 mem_cgroup_charge_file+0x8b/0xd0 shmem_getpage_gfp+0x66b/0x7b0 shmem_file_splice_read+0x18f/0x430 splice_direct_to_actor+0xa2/0x1c0 do_lo_receive+0x5a/0x60 [loop] loop_thread+0x298/0x720 [loop] kthread+0xc6/0xe0 ret_from_fork+0x7c/0xb0 Also Branimir Maksimovic reported the following oops which is tiggered for the swapcache charge path from the accounting code for kernel threads: CPU: 1 PID: 160 Comm: kworker/u8:5 Tainted: P OE 3.15.0-rc5-core2-custom #159 Hardware name: System manufacturer System Product Name/MAXIMUSV GENE, BIOS 1903 08/19/2013 task: ffff880404e349b0 ti: ffff88040486a000 task.ti: ffff88040486a000 RIP: get_mem_cgroup_from_mm.isra.42+0x2b/0x60 Call Trace: __mem_cgroup_try_charge_swapin+0x45/0xf0 mem_cgroup_charge_file+0x9c/0xe0 shmem_getpage_gfp+0x62c/0x770 shmem_write_begin+0x38/0x40 generic_perform_write+0xc5/0x1c0 __generic_file_aio_write+0x1d1/0x3f0 generic_file_aio_write+0x4f/0xc0 do_sync_write+0x5a/0x90 do_acct_process+0x4b1/0x550 acct_process+0x6d/0xa0 do_exit+0x827/0xa70 kthread+0xc3/0xf0 This patch fixes the issue by reintroducing mm check into get_mem_cgroup_from_mm. We could do the same trick in __mem_cgroup_try_charge_swapin as we do for the regular page cache path but it is not worth troubles. The check is not that expensive and it is better to have get_mem_cgroup_from_mm more robust. [1] - http://marc.info/?l=linux-mm&m=139463617808941&w=2 Fixes: 03583f1a631c ("memcg: remove unnecessary !mm check from try_get_mem_cgroup_from_mm()") Reported-and-tested-by: Stephan Kulow <coolo@suse.com> Reported-by: Branimir Maksimovic <branimir.maksimovic@gmail.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 55231e5
File | Mode | Size |
---|---|---|
Kconfig | -rw-r--r-- | 20.6 KB |
Kconfig.debug | -rw-r--r-- | 1015 bytes |
Makefile | -rw-r--r-- | 2.2 KB |
backing-dev.c | -rw-r--r-- | 16.7 KB |
balloon_compaction.c | -rw-r--r-- | 9.7 KB |
bootmem.c | -rw-r--r-- | 20.8 KB |
bounce.c | -rw-r--r-- | 6.4 KB |
cleancache.c | -rw-r--r-- | 12.7 KB |
compaction.c | -rw-r--r-- | 33.8 KB |
debug-pagealloc.c | -rw-r--r-- | 2.1 KB |
dmapool.c | -rw-r--r-- | 13.1 KB |
early_ioremap.c | -rw-r--r-- | 5.4 KB |
fadvise.c | -rw-r--r-- | 3.6 KB |
failslab.c | -rw-r--r-- | 1.3 KB |
filemap.c | -rw-r--r-- | 72.4 KB |
filemap_xip.c | -rw-r--r-- | 11.3 KB |
fremap.c | -rw-r--r-- | 7.2 KB |
frontswap.c | -rw-r--r-- | 13.5 KB |
highmem.c | -rw-r--r-- | 9.9 KB |
huge_memory.c | -rw-r--r-- | 76.1 KB |
hugetlb.c | -rw-r--r-- | 94.2 KB |
hugetlb_cgroup.c | -rw-r--r-- | 10.1 KB |
hwpoison-inject.c | -rw-r--r-- | 3.3 KB |
init-mm.c | -rw-r--r-- | 619 bytes |
internal.h | -rw-r--r-- | 11.8 KB |
interval_tree.c | -rw-r--r-- | 3.2 KB |
iov_iter.c | -rw-r--r-- | 5.3 KB |
kmemcheck.c | -rw-r--r-- | 2.8 KB |
kmemleak-test.c | -rw-r--r-- | 3.3 KB |
kmemleak.c | -rw-r--r-- | 52.4 KB |
ksm.c | -rw-r--r-- | 63.4 KB |
list_lru.c | -rw-r--r-- | 3.4 KB |
maccess.c | -rw-r--r-- | 1.6 KB |
madvise.c | -rw-r--r-- | 14.2 KB |
memblock.c | -rw-r--r-- | 42.9 KB |
memcontrol.c | -rw-r--r-- | 190.8 KB |
memory-failure.c | -rw-r--r-- | 46.4 KB |
memory.c | -rw-r--r-- | 120.2 KB |
memory_hotplug.c | -rw-r--r-- | 48.4 KB |
mempolicy.c | -rw-r--r-- | 71.6 KB |
mempool.c | -rw-r--r-- | 10.5 KB |
migrate.c | -rw-r--r-- | 49.0 KB |
mincore.c | -rw-r--r-- | 7.8 KB |
mlock.c | -rw-r--r-- | 22.6 KB |
mm_init.c | -rw-r--r-- | 5.0 KB |
mmap.c | -rw-r--r-- | 86.5 KB |
mmu_context.c | -rw-r--r-- | 1.3 KB |
mmu_notifier.c | -rw-r--r-- | 9.5 KB |
mmzone.c | -rw-r--r-- | 2.4 KB |
mprotect.c | -rw-r--r-- | 10.7 KB |
mremap.c | -rw-r--r-- | 15.0 KB |
msync.c | -rw-r--r-- | 2.4 KB |
nobootmem.c | -rw-r--r-- | 10.8 KB |
nommu.c | -rw-r--r-- | 53.4 KB |
oom_kill.c | -rw-r--r-- | 19.8 KB |
page-writeback.c | -rw-r--r-- | 75.2 KB |
page_alloc.c | -rw-r--r-- | 181.7 KB |
page_cgroup.c | -rw-r--r-- | 12.0 KB |
page_io.c | -rw-r--r-- | 9.0 KB |
page_isolation.c | -rw-r--r-- | 7.5 KB |
pagewalk.c | -rw-r--r-- | 5.9 KB |
percpu-km.c | -rw-r--r-- | 2.8 KB |
percpu-vm.c | -rw-r--r-- | 12.9 KB |
percpu.c | -rw-r--r-- | 56.9 KB |
pgtable-generic.c | -rw-r--r-- | 5.2 KB |
process_vm_access.c | -rw-r--r-- | 10.2 KB |
quicklist.c | -rw-r--r-- | 2.4 KB |
readahead.c | -rw-r--r-- | 15.6 KB |
rmap.c | -rw-r--r-- | 47.9 KB |
shmem.c | -rw-r--r-- | 76.6 KB |
slab.c | -rw-r--r-- | 110.7 KB |
slab.h | -rw-r--r-- | 7.9 KB |
slab_common.c | -rw-r--r-- | 17.1 KB |
slob.c | -rw-r--r-- | 15.7 KB |
slub.c | -rw-r--r-- | 127.3 KB |
sparse-vmemmap.c | -rw-r--r-- | 6.0 KB |
sparse.c | -rw-r--r-- | 20.9 KB |
swap.c | -rw-r--r-- | 29.2 KB |
swap_state.c | -rw-r--r-- | 12.9 KB |
swapfile.c | -rw-r--r-- | 76.8 KB |
truncate.c | -rw-r--r-- | 22.5 KB |
util.c | -rw-r--r-- | 11.9 KB |
vmacache.c | -rw-r--r-- | 2.6 KB |
vmalloc.c | -rw-r--r-- | 68.2 KB |
vmpressure.c | -rw-r--r-- | 11.4 KB |
vmscan.c | -rw-r--r-- | 107.9 KB |
vmstat.c | -rw-r--r-- | 35.2 KB |
workingset.c | -rw-r--r-- | 13.6 KB |
zbud.c | -rw-r--r-- | 15.9 KB |
zsmalloc.c | -rw-r--r-- | 28.7 KB |
zswap.c | -rw-r--r-- | 24.1 KB |
Computing file changes ...