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authorYisheng Xie <xieyisheng1@huawei.com>2017-11-29 16:11:08 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-29 18:40:43 -0800
commitbde5f6bc68db51128f875a756e9082a6c6ff7b4c (patch)
tree76d26ad04100d9b378fc2ad520b299c69fef528f /mm
parentedbddb83a15b4361d8c3bf00aabee85fd3ef4d80 (diff)
downloadlinux-bde5f6bc68db51128f875a756e9082a6c6ff7b4c.tar.gz
kmemleak: add scheduling point to kmemleak_scan()
kmemleak_scan() will scan struct page for each node and it can be really
large and resulting in a soft lockup.  We have seen a soft lockup when
do scan while compile kernel:

  watchdog: BUG: soft lockup - CPU#53 stuck for 22s! [bash:10287]
 [...]
  Call Trace:
   kmemleak_scan+0x21a/0x4c0
   kmemleak_write+0x312/0x350
   full_proxy_write+0x5a/0xa0
   __vfs_write+0x33/0x150
   vfs_write+0xad/0x1a0
   SyS_write+0x52/0xc0
   do_syscall_64+0x61/0x1a0
   entry_SYSCALL64_slow_path+0x25/0x25

Fix this by adding cond_resched every MAX_SCAN_SIZE.

Link: http://lkml.kernel.org/r/1511439788-20099-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/kmemleak.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index e4738d5e9b8c..3d4781756d50 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1523,6 +1523,8 @@ static void kmemleak_scan(void)
 			if (page_count(page) == 0)
 				continue;
 			scan_block(page, page + 1, NULL);
+			if (!(pfn % (MAX_SCAN_SIZE / sizeof(*page))))
+				cond_resched();
 		}
 	}
 	put_online_mems();