From: Yisheng Xie <xieyisheng1@xxxxxxxxxx> Subject: 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: [ 220.561051] watchdog: BUG: soft lockup - CPU#53 stuck for 22s! [bash:10287] [...] [ 220.753837] Call Trace: [ 220.756296] kmemleak_scan+0x21a/0x4c0 [ 220.760034] kmemleak_write+0x312/0x350 [ 220.763866] ? do_wp_page+0x147/0x4c0 [ 220.767521] full_proxy_write+0x5a/0xa0 [ 220.771351] __vfs_write+0x33/0x150 [ 220.774833] ? __inode_security_revalidate+0x4c/0x60 [ 220.779782] ? selinux_file_permission+0xda/0x130 [ 220.784479] ? _cond_resched+0x15/0x30 [ 220.788221] vfs_write+0xad/0x1a0 [ 220.791529] SyS_write+0x52/0xc0 [ 220.794758] do_syscall_64+0x61/0x1a0 [ 220.798411] 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@xxxxxxxxxx Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx> Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx> Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/kmemleak.c | 2 ++ 1 file changed, 2 insertions(+) diff -puN mm/kmemleak.c~kmemleak-add-scheduling-point-to-kmemleak_scan mm/kmemleak.c --- a/mm/kmemleak.c~kmemleak-add-scheduling-point-to-kmemleak_scan +++ a/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(); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
