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* [PATCH] mm: vmalloc: add cond_resched() in __vunmap()
@ 2021-06-22 22:50 Rafael Aquini
  2021-06-23  8:43 ` Nicholas Piggin
                   ` (3 more replies)
  0 siblings, 4 replies; 14+ messages in thread
From: Rafael Aquini @ 2021-06-22 22:50 UTC (permalink / raw)
  To: linux-mm; +Cc: Andrew Morton, linux-kernel

On non-preemptible kernel builds the watchdog can complain
about soft lockups when vfree() is called against large
vmalloc areas:

[  210.851798] kvmalloc-test: vmalloc(2199023255552) succeeded
[  238.654842] watchdog: BUG: soft lockup - CPU#181 stuck for 26s! [rmmod:5203]
[  238.662716] Modules linked in: kvmalloc_test(OE-) ...
[  238.772671] CPU: 181 PID: 5203 Comm: rmmod Tainted: G S         OE     5.13.0-rc7+ #1
[  238.781413] Hardware name: Intel Corporation PURLEY/PURLEY, BIOS PLYXCRB1.86B.0553.D01.1809190614 09/19/2018
[  238.792383] RIP: 0010:free_unref_page+0x52/0x60
[  238.797447] Code: 48 c1 fd 06 48 89 ee e8 9c d0 ff ff 84 c0 74 19 9c 41 5c fa 48 89 ee 48 89 df e8 b9 ea ff ff 41 f7 c4 00 02 00 00 74 01 fb 5b <5d> 41 5c c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f0 29 77
[  238.818406] RSP: 0018:ffffb4d87868fe98 EFLAGS: 00000206
[  238.824236] RAX: 0000000000000000 RBX: 000000001da0c945 RCX: ffffb4d87868fe40
[  238.832200] RDX: ffffd79d3beed108 RSI: ffffd7998501dc08 RDI: ffff9c6fbffd7010
[  238.840166] RBP: 000000000d518cbd R08: ffffd7998501dc08 R09: 0000000000000001
[  238.848131] R10: 0000000000000000 R11: ffffd79d3beee088 R12: 0000000000000202
[  238.856095] R13: ffff9e5be3eceec0 R14: 0000000000000000 R15: 0000000000000000
[  238.864059] FS:  00007fe082c2d740(0000) GS:ffff9f4c69b40000(0000) knlGS:0000000000000000
[  238.873089] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  238.879503] CR2: 000055a000611128 CR3: 000000f6094f6006 CR4: 00000000007706e0
[  238.887467] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  238.895433] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  238.903397] PKRU: 55555554
[  238.906417] Call Trace:
[  238.909149]  __vunmap+0x17c/0x220
[  238.912851]  __x64_sys_delete_module+0x13a/0x250
[  238.918008]  ? syscall_trace_enter.isra.20+0x13c/0x1b0
[  238.923746]  do_syscall_64+0x39/0x80
[  238.927740]  entry_SYSCALL_64_after_hwframe+0x44/0xae

Like in other range zapping routines that iterate over
a large list, lets just add cond_resched() within __vunmap()'s
page-releasing loop in order to avoid the watchdog splats.

Signed-off-by: Rafael Aquini <aquini@redhat.com>
---
 mm/vmalloc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a13ac524f6ff..cd4b23d65748 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2564,6 +2564,7 @@ static void __vunmap(const void *addr, int deallocate_pages)
 
 			BUG_ON(!page);
 			__free_pages(page, page_order);
+			cond_resched();
 		}
 		atomic_long_sub(area->nr_pages, &nr_vmalloc_pages);
 
-- 
2.26.3


^ permalink raw reply related	[flat|nested] 14+ messages in thread

end of thread, other threads:[~2021-06-29 14:12 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-22 22:50 [PATCH] mm: vmalloc: add cond_resched() in __vunmap() Rafael Aquini
2021-06-23  8:43 ` Nicholas Piggin
2021-06-23 17:30   ` Rafael Aquini
2021-06-23 11:27 ` Uladzislau Rezki
2021-06-23 17:34   ` Rafael Aquini
2021-06-23 20:14     ` Uladzislau Rezki
2021-06-23 12:11 ` Aaron Tomlin
2021-06-24 12:21 ` Michal Hocko
2021-06-24 14:23   ` Uladzislau Rezki
2021-06-25  8:51     ` Michal Hocko
2021-06-25 16:00       ` Uladzislau Rezki
2021-06-28 12:46         ` Michal Hocko
2021-06-28 16:40           ` Uladzislau Rezki
2021-06-29 14:11             ` Michal Hocko

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