]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
mm: memcontrol: fix GFP_NOFS recursion in memory.high enforcement
authorJohannes Weiner <hannes@cmpxchg.org>
Thu, 14 Sep 2023 15:21:39 +0000 (11:21 -0400)
committerAndrew Morton <akpm@linux-foundation.org>
Tue, 19 Sep 2023 20:21:34 +0000 (13:21 -0700)
commit9ea9cb00a82b53ec39630eac718776d37e41b35a
treecbdf3933fa7a9000471fed4ef6748b285a2c3696
parent0c7752d5b1ac62c8b926c907f34073ef7e9ad42b
mm: memcontrol: fix GFP_NOFS recursion in memory.high enforcement

Breno and Josef report a deadlock scenario from cgroup reclaim
re-entering the filesystem:

[  361.546690] ======================================================
[  361.559210] WARNING: possible circular locking dependency detected
[  361.571703] 6.5.0-0_fbk700_debug_rc0_kbuilder_13159_gbf787a128001 #1 Tainted: G S          E
[  361.589704] ------------------------------------------------------
[  361.602277] find/9315 is trying to acquire lock:
[  361.611625] ffff88837ba140c0 (&delayed_node->mutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0x68/0x4f0
[  361.631437]
[  361.631437] but task is already holding lock:
[  361.643243] ffff8881765b8678 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock+0x1e/0x40

[  362.904457]  mutex_lock_nested+0x1c/0x30
[  362.912414]  __btrfs_release_delayed_node+0x68/0x4f0
[  362.922460]  btrfs_evict_inode+0x301/0x770
[  362.982726]  evict+0x17c/0x380
[  362.988944]  prune_icache_sb+0x100/0x1d0
[  363.005559]  super_cache_scan+0x1f8/0x260
[  363.013695]  do_shrink_slab+0x2a2/0x540
[  363.021489]  shrink_slab_memcg+0x237/0x3d0
[  363.050606]  shrink_slab+0xa7/0x240
[  363.083382]  shrink_node_memcgs+0x262/0x3b0
[  363.091870]  shrink_node+0x1a4/0x720
[  363.099150]  shrink_zones+0x1f6/0x5d0
[  363.148798]  do_try_to_free_pages+0x19b/0x5e0
[  363.157633]  try_to_free_mem_cgroup_pages+0x266/0x370
[  363.190575]  reclaim_high+0x16f/0x1f0
[  363.208409]  mem_cgroup_handle_over_high+0x10b/0x270
[  363.246678]  try_charge_memcg+0xaf2/0xc70
[  363.304151]  charge_memcg+0xf0/0x350
[  363.320070]  __mem_cgroup_charge+0x28/0x40
[  363.328371]  __filemap_add_folio+0x870/0xd50
[  363.371303]  filemap_add_folio+0xdd/0x310
[  363.399696]  __filemap_get_folio+0x2fc/0x7d0
[  363.419086]  pagecache_get_page+0xe/0x30
[  363.427048]  alloc_extent_buffer+0x1cd/0x6a0
[  363.435704]  read_tree_block+0x43/0xc0
[  363.443316]  read_block_for_search+0x361/0x510
[  363.466690]  btrfs_search_slot+0xc8c/0x1520

This is caused by the mem_cgroup_handle_over_high() not respecting the
gfp_mask of the allocation context.  We used to only call this function on
resume to userspace, where no locks were held.  But c9afe31ec443 ("memcg:
synchronously enforce memory.high for large overcharges") added a call
from the allocation context without considering the gfp.

Link: https://lkml.kernel.org/r/20230914152139.100822-1-hannes@cmpxchg.org
Fixes: c9afe31ec443 ("memcg: synchronously enforce memory.high for large overcharges")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Breno Leitao <leitao@debian.org>
Reported-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org> [5.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
include/linux/memcontrol.h
include/linux/resume_user_mode.h
mm/memcontrol.c