The patch titled
Subject: mm: vmalloc: add cond_resched() in __vunmap()
has been added to the -mm tree. Its filename is
mm-vmalloc-add-cond_resched-in-__vunmap.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-vmalloc-add-cond_resched-in-__vunmap.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmalloc-add-cond_resched-in-__vunmap.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Rafael Aquini <aquini@xxxxxxxxxx>
Subject: mm: vmalloc: add cond_resched() in __vunmap()
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.
Link: https://lkml.kernel.org/r/20210622225030.478384-1-aquini@xxxxxxxxxx
Signed-off-by: Rafael Aquini <aquini@xxxxxxxxxx>
Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 1 +
1 file changed, 1 insertion(+)
--- a/mm/vmalloc.c~mm-vmalloc-add-cond_resched-in-__vunmap
+++ a/mm/vmalloc.c
@@ -2564,6 +2564,7 @@ static void __vunmap(const void *addr, i
BUG_ON(!page);
__free_pages(page, page_order);
+ cond_resched();
}
atomic_long_sub(area->nr_pages, &nr_vmalloc_pages);
_
Patches currently in -mm which might be from aquini@xxxxxxxxxx are
mm-vmalloc-add-cond_resched-in-__vunmap.patch
