On Fri, May 10, 2024 at 06:01:31PM +0800, hailong.liu@xxxxxxxx wrote:
> From: "Hailong.Liu" <hailong.liu@xxxxxxxx>
>
> commit a421ef303008 ("mm: allow !GFP_KERNEL allocations for kvmalloc")
> includes support for __GFP_NOFAIL, but it presents a conflict with
> commit dd544141b9eb ("vmalloc: back off when the current task is
> OOM-killed"). A possible scenario is as follows:
>
> process-a
> __vmalloc_node_range(GFP_KERNEL | __GFP_NOFAIL)
> __vmalloc_area_node()
> vm_area_alloc_pages()
> --> oom-killer send SIGKILL to process-a
> if (fatal_signal_pending(current)) break;
> --> return NULL;
>
> To fix this, do not check fatal_signal_pending() in vm_area_alloc_pages()
> if __GFP_NOFAIL set.
>
> Fixes: 9376130c390a ("mm/vmalloc: add support for __GFP_NOFAIL")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> Suggested-by: Barry Song <21cnbao@xxxxxxxxx>
> Reported-by: Oven <liyangouwen1@xxxxxxxx>
> Signed-off-by: Hailong.Liu <hailong.liu@xxxxxxxx>
> ---
> mm/vmalloc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 125427cbdb87..109272b8ee2e 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3492,7 +3492,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
> {
> unsigned int nr_allocated = 0;
> gfp_t alloc_gfp = gfp;
> - bool nofail = false;
> + bool nofail = gfp & __GFP_NOFAIL;
> struct page *page;
> int i;
>
> @@ -3549,12 +3549,11 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
> * and compaction etc.
> */
> alloc_gfp &= ~__GFP_NOFAIL;
> - nofail = true;
> }
>
> /* High-order pages or fallback path if "bulk" fails. */
> while (nr_allocated < nr_pages) {
> - if (fatal_signal_pending(current))
> + if (!nofail && fatal_signal_pending(current))
> break;
>
> if (nid == NUMA_NO_NODE)
> ---
> Changes since RFC v1 [1]:
> - Remove RFC tag
> - Add fixes, per Michal
> - Use nofail instead of gfp & __GFP_NOFAIL, per Barry & Michal
> - Modify commit log, per Barry
>
> [1] https://lore.kernel.org/all/20240508125808.28882-1-hailong.liu@xxxxxxxx/
>
> This issue occurred during OPLUS KASAN TEST. Below is part of the log
> -> oom-killer sends signal to process
> [65731.222840] [ T1308] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/apps/uid_10198,task=gs.intelligence,pid=32454,uid=10198
>
> [65731.259685] [T32454] Call trace:
> [65731.259698] [T32454] dump_backtrace+0xf4/0x118
> [65731.259734] [T32454] show_stack+0x18/0x24
> [65731.259756] [T32454] dump_stack_lvl+0x60/0x7c
> [65731.259781] [T32454] dump_stack+0x18/0x38
> [65731.259800] [T32454] mrdump_common_die+0x250/0x39c [mrdump]
> [65731.259936] [T32454] ipanic_die+0x20/0x34 [mrdump]
> [65731.260019] [T32454] atomic_notifier_call_chain+0xb4/0xfc
> [65731.260047] [T32454] notify_die+0x114/0x198
> [65731.260073] [T32454] die+0xf4/0x5b4
> [65731.260098] [T32454] die_kernel_fault+0x80/0x98
> [65731.260124] [T32454] __do_kernel_fault+0x160/0x2a8
> [65731.260146] [T32454] do_bad_area+0x68/0x148
> [65731.260174] [T32454] do_mem_abort+0x151c/0x1b34
> [65731.260204] [T32454] el1_abort+0x3c/0x5c
> [65731.260227] [T32454] el1h_64_sync_handler+0x54/0x90
> [65731.260248] [T32454] el1h_64_sync+0x68/0x6c
>
> [65731.260269] [T32454] z_erofs_decompress_queue+0x7f0/0x2258
> --> be->decompressed_pages = kvcalloc(be->nr_pages, sizeof(struct page *), GFP_KERNEL | __GFP_NOFAIL);
> kernel panic by NULL pointer dereference.
> erofs assume kvmalloc with __GFP_NOFAIL never return NULL.
> [65731.260293] [T32454] z_erofs_runqueue+0xf30/0x104c
> [65731.260314] [T32454] z_erofs_readahead+0x4f0/0x968
> [65731.260339] [T32454] read_pages+0x170/0xadc
> [65731.260364] [T32454] page_cache_ra_unbounded+0x874/0xf30
> [65731.260388] [T32454] page_cache_ra_order+0x24c/0x714
> [65731.260411] [T32454] filemap_fault+0xbf0/0x1a74
> [65731.260437] [T32454] __do_fault+0xd0/0x33c
> [65731.260462] [T32454] handle_mm_fault+0xf74/0x3fe0
> [65731.260486] [T32454] do_mem_abort+0x54c/0x1b34
> [65731.260509] [T32454] el0_da+0x44/0x94
> [65731.260531] [T32454] el0t_64_sync_handler+0x98/0xb4
> [65731.260553] [T32454] el0t_64_sync+0x198/0x19c
> --
> 2.34.1
>
Makes sense to me:
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
--
Uladzislau Rezki
