On Tue, Mar 28, 2023 at 11:50:53AM +0000, Yafang Shao wrote:
> There're some suspicious warn_alloc on my test serer, for example,
>
> [13366.518837] warn_alloc: 81 callbacks suppressed
> [13366.518841] test_verifier: vmalloc error: size 4096, page order 0, failed to allocate pages, mode:0x500dc2(GFP_HIGHUSER|__GFP_ZERO|__GFP_ACCOUNT), nodemask=(null),cpuset=/,mems_allowed=0-1
> [13366.522240] CPU: 30 PID: 722463 Comm: test_verifier Kdump: loaded Tainted: G W O 6.2.0+ #638
> [13366.524216] Call Trace:
> [13366.524702] <TASK>
> [13366.525148] dump_stack_lvl+0x6c/0x80
> [13366.525712] dump_stack+0x10/0x20
> [13366.526239] warn_alloc+0x119/0x190
> [13366.526783] ? alloc_pages_bulk_array_mempolicy+0x9e/0x2a0
> [13366.527470] __vmalloc_area_node+0x546/0x5b0
> [13366.528066] __vmalloc_node_range+0xc2/0x210
> [13366.528660] __vmalloc_node+0x42/0x50
> [13366.529186] ? bpf_prog_realloc+0x53/0xc0
> [13366.529743] __vmalloc+0x1e/0x30
> [13366.530235] bpf_prog_realloc+0x53/0xc0
> [13366.530771] bpf_patch_insn_single+0x80/0x1b0
> [13366.531351] bpf_jit_blind_constants+0xe9/0x1c0
> [13366.531932] ? __free_pages+0xee/0x100
> [13366.532457] ? free_large_kmalloc+0x58/0xb0
> [13366.533002] bpf_int_jit_compile+0x8c/0x5e0
> [13366.533546] bpf_prog_select_runtime+0xb4/0x100
> [13366.534108] bpf_prog_load+0x6b1/0xa50
> [13366.534610] ? perf_event_task_tick+0x96/0xb0
> [13366.535151] ? security_capable+0x3a/0x60
> [13366.535663] __sys_bpf+0xb38/0x2190
> [13366.536120] ? kvm_clock_get_cycles+0x9/0x10
> [13366.536643] __x64_sys_bpf+0x1c/0x30
> [13366.537094] do_syscall_64+0x38/0x90
> [13366.537554] entry_SYSCALL_64_after_hwframe+0x72/0xdc
> [13366.538107] RIP: 0033:0x7f78310f8e29
> [13366.538561] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 17 e0 2c 00 f7 d8 64 89 01 48
> [13366.540286] RSP: 002b:00007ffe2a61fff8 EFLAGS: 00000206 ORIG_RAX: 0000000000000141
> [13366.541031] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f78310f8e29
> [13366.541749] RDX: 0000000000000080 RSI: 00007ffe2a6200b0 RDI: 0000000000000005
> [13366.542470] RBP: 00007ffe2a620010 R08: 00007ffe2a6202a0 R09: 00007ffe2a6200b0
> [13366.543183] R10: 00000000000f423e R11: 0000000000000206 R12: 0000000000407800
> [13366.543900] R13: 00007ffe2a620540 R14: 0000000000000000 R15: 0000000000000000
> [13366.544623] </TASK>
> [13366.545260] Mem-Info:
> [13366.546121] active_anon:81319 inactive_anon:20733 isolated_anon:0
> active_file:69450 inactive_file:5624 isolated_file:0
> unevictable:0 dirty:10 writeback:0
> slab_reclaimable:69649 slab_unreclaimable:48930
> mapped:27400 shmem:12868 pagetables:4929
> sec_pagetables:0 bounce:0
> kernel_misc_reclaimable:0
> free:15870308 free_pcp:142935 free_cma:0
> [13366.551886] Node 0 active_anon:224836kB inactive_anon:33528kB active_file:175692kB inactive_file:13752kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:59248kB dirty:32kB writeback:0kB shmem:18252kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:4616kB pagetables:10664kB sec_pagetables:0kB all_unreclaimable? no
> [13366.555184] Node 1 active_anon:100440kB inactive_anon:49404kB active_file:102108kB inactive_file:8744kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:50352kB dirty:8kB writeback:0kB shmem:33220kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:3896kB pagetables:9052kB sec_pagetables:0kB all_unreclaimable? no
> [13366.558262] Node 0 DMA free:15360kB boost:0kB min:304kB low:380kB high:456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> [13366.560821] lowmem_reserve[]: 0 2735 31873 31873 31873
> [13366.561981] Node 0 DMA32 free:2790904kB boost:0kB min:56028kB low:70032kB high:84036kB reserved_highatomic:0KB active_anon:1936kB inactive_anon:20kB active_file:396kB inactive_file:344kB unevictable:0kB writepending:0kB present:3129200kB managed:2801520kB mlocked:0kB bounce:0kB free_pcp:5188kB local_pcp:0kB free_cma:0kB
> [13366.565148] lowmem_reserve[]: 0 0 29137 29137 29137
> [13366.566168] Node 0 Normal free:28533824kB boost:0kB min:596740kB low:745924kB high:895108kB reserved_highatomic:28672KB active_anon:222900kB inactive_anon:33508kB active_file:175296kB inactive_file:13408kB unevictable:0kB writepending:32kB present:30408704kB managed:29837172kB mlocked:0kB bounce:0kB free_pcp:295724kB local_pcp:0kB free_cma:0kB
> [13366.569485] lowmem_reserve[]: 0 0 0 0 0
> [13366.570416] Node 1 Normal free:32141144kB boost:0kB min:660504kB low:825628kB high:990752kB reserved_highatomic:69632KB active_anon:100440kB inactive_anon:49404kB active_file:102108kB inactive_file:8744kB unevictable:0kB writepending:8kB present:33554432kB managed:33025372kB mlocked:0kB bounce:0kB free_pcp:270880kB local_pcp:46860kB free_cma:0kB
> [13366.573403] lowmem_reserve[]: 0 0 0 0 0
> [13366.574015] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15360kB
> [13366.575474] Node 0 DMA32: 782*4kB (UME) 756*8kB (UME) 736*16kB (UME) 745*32kB (UME) 694*64kB (UME) 653*128kB (UME) 595*256kB (UME) 552*512kB (UME) 454*1024kB (UME) 347*2048kB (UME) 246*4096kB (UME) = 2790904kB
> [13366.577442] Node 0 Normal: 33856*4kB (UMEH) 51815*8kB (UMEH) 42418*16kB (UMEH) 36272*32kB (UMEH) 22195*64kB (UMEH) 10296*128kB (UMEH) 7238*256kB (UMEH) 5638*512kB (UEH) 5337*1024kB (UMEH) 3506*2048kB (UMEH) 1470*4096kB (UME) = 28533784kB
> [13366.580460] Node 1 Normal: 15776*4kB (UMEH) 37485*8kB (UMEH) 29509*16kB (UMEH) 21420*32kB (UMEH) 14818*64kB (UMEH) 13051*128kB (UMEH) 9918*256kB (UMEH) 7374*512kB (UMEH) 5397*1024kB (UMEH) 3887*2048kB (UMEH) 2002*4096kB (UME) = 32141240kB
> [13366.583027] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
> [13366.584380] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
> [13366.585702] Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
> [13366.587042] Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
> [13366.588372] 87386 total pagecache pages
> [13366.589266] 0 pages in swap cache
> [13366.590327] Free swap = 0kB
> [13366.591227] Total swap = 0kB
> [13366.592142] 16777082 pages RAM
> [13366.593057] 0 pages HighMem/MovableOnly
> [13366.594037] 357226 pages reserved
> [13366.594979] 0 pages hwpoisoned
>
> This failure really confuse me as there're still lots of available
> pages. Finally I figured out it was caused by a fatal signal. When a
> process is allocating memory via vm_area_alloc_pages(), it will break
> directly even if it hasn't allocated the requested pages when it
> receives a fatal signal. In that case, we shouldn't show this warn_alloc,
> as it is useless. We only need to show this warning when there're really
> no enough pages.
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> mm/vmalloc.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index ef910bf..7cba712 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3024,9 +3024,10 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
> * allocation request, free them via vfree() if any.
> */
> if (area->nr_pages != nr_small_pages) {
> - warn_alloc(gfp_mask, NULL,
> - "vmalloc error: size %lu, page order %u, failed to allocate pages",
> - area->nr_pages * PAGE_SIZE, page_order);
> + if (!fatal_signal_pending(current))
> + warn_alloc(gfp_mask, NULL,
> + "vmalloc error: size %lu, page order %u, failed to allocate pages",
> + area->nr_pages * PAGE_SIZE, page_order);
> goto fail;
> }
>
This does align with vm_area_alloc_pages() breaking out of a loop due to a
fatal signal and this would essentially be the other side of it, and this
is another means by which this can fail (+ thus otherwise provide an
inaccurate error mesage) so I think this is definitely needed, though I'd
like a comment like e.g.:-
/* vm_area_alloc_pages() can also fail due to a fatal signal */
Other than this nit:-
Reviewed-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
> --
> 1.8.3.1
>
>
