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authorBhupesh Sharma <bhsharma@redhat.com>2020-07-23 21:15:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-07-24 12:42:41 -0700
commit82ff165cd35110d4e380b55927bbd74dcb564998 (patch)
tree379953d277a483141e87c1eaefced31ae8946148
parent45779b036d3d2870633443a9f9bd03c177befbf5 (diff)
downloadlinux-82ff165cd35110d4e380b55927bbd74dcb564998.tar.bz2
mm/memcontrol: fix OOPS inside mem_cgroup_get_nr_swap_pages()
Prabhakar reported an OOPS inside mem_cgroup_get_nr_swap_pages() function in a corner case seen on some arm64 boards when kdump kernel runs with "cgroup_disable=memory" passed to the kdump kernel via bootargs. The root-cause behind the same is that currently mem_cgroup_swap_init() function is implemented as a subsys_initcall() call instead of a core_initcall(), this means 'cgroup_memory_noswap' still remains set to the default value (false) even when memcg is disabled via "cgroup_disable=memory" boot parameter. This may result in premature OOPS inside mem_cgroup_get_nr_swap_pages() function in corner cases: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000188 Mem abort info: ESR = 0x96000006 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000006 CM = 0, WnR = 0 [0000000000000188] user address but active_mm is swapper Internal error: Oops: 96000006 [#1] SMP Modules linked in: <..snip..> Call trace: mem_cgroup_get_nr_swap_pages+0x9c/0xf4 shrink_lruvec+0x404/0x4f8 shrink_node+0x1a8/0x688 do_try_to_free_pages+0xe8/0x448 try_to_free_pages+0x110/0x230 __alloc_pages_slowpath.constprop.106+0x2b8/0xb48 __alloc_pages_nodemask+0x2ac/0x2f8 alloc_page_interleave+0x20/0x90 alloc_pages_current+0xdc/0xf8 atomic_pool_expand+0x60/0x210 __dma_atomic_pool_init+0x50/0xa4 dma_atomic_pool_init+0xac/0x158 do_one_initcall+0x50/0x218 kernel_init_freeable+0x22c/0x2d0 kernel_init+0x18/0x110 ret_from_fork+0x10/0x18 Code: aa1403e3 91106000 97f82a27 14000011 (f940c663) ---[ end trace 9795948475817de4 ]--- Kernel panic - not syncing: Fatal exception Rebooting in 10 seconds.. Fixes: eccb52e78809 ("mm: memcontrol: prepare swap controller setup for integration") Reported-by: Prabhakar Kushwaha <pkushwaha@marvell.com> Signed-off-by: Bhupesh Sharma <bhsharma@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: James Morse <james.morse@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Link: http://lkml.kernel.org/r/1593641660-13254-2-git-send-email-bhsharma@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 19622328e4b5..c75c4face02e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -7186,6 +7186,13 @@ static struct cftype memsw_files[] = {
{ }, /* terminate */
};
+/*
+ * If mem_cgroup_swap_init() is implemented as a subsys_initcall()
+ * instead of a core_initcall(), this could mean cgroup_memory_noswap still
+ * remains set to false even when memcg is disabled via "cgroup_disable=memory"
+ * boot parameter. This may result in premature OOPS inside
+ * mem_cgroup_get_nr_swap_pages() function in corner cases.
+ */
static int __init mem_cgroup_swap_init(void)
{
/* No memory control -> no swap control */
@@ -7200,6 +7207,6 @@ static int __init mem_cgroup_swap_init(void)
return 0;
}
-subsys_initcall(mem_cgroup_swap_init);
+core_initcall(mem_cgroup_swap_init);
#endif /* CONFIG_MEMCG_SWAP */