The patch titled
Subject: fs/ocfs2/dlm/dlmdebug.c: fix a sleep-in-atomic-context bug in dlm_print_one_mle()
has been added to the -mm tree. Its filename is
fs-ocfs2-dlm-fix-a-sleep-in-atomic-context-bug-in-dlm_print_one_mle.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fs-ocfs2-dlm-fix-a-sleep-in-atomic-context-bug-in-dlm_print_one_mle.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fs-ocfs2-dlm-fix-a-sleep-in-atomic-context-bug-in-dlm_print_one_mle.patch
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------------------------------------------------------
From: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Subject: fs/ocfs2/dlm/dlmdebug.c: fix a sleep-in-atomic-context bug in dlm_print_one_mle()
The kernel module may sleep with holding a spinlock.
The function call paths (from bottom to top) in Linux-4.16 are:
[FUNC] get_zeroed_page(GFP_NOFS)
fs/ocfs2/dlm/dlmdebug.c, 332: get_zeroed_page in dlm_print_one_mle
fs/ocfs2/dlm/dlmmaster.c, 240: dlm_print_one_mle in __dlm_put_mle
fs/ocfs2/dlm/dlmmaster.c, 255: __dlm_put_mle in dlm_put_mle
fs/ocfs2/dlm/dlmmaster.c, 254: spin_lock in dlm_put_ml
[FUNC] get_zeroed_page(GFP_NOFS)
fs/ocfs2/dlm/dlmdebug.c, 332: get_zeroed_page in dlm_print_one_mle
fs/ocfs2/dlm/dlmmaster.c, 240: dlm_print_one_mle in __dlm_put_mle
fs/ocfs2/dlm/dlmmaster.c, 222: __dlm_put_mle in dlm_put_mle_inuse
fs/ocfs2/dlm/dlmmaster.c, 219: spin_lock in dlm_put_mle_inuse
To fix this bug, GFP_NOFS is replaced with GFP_ATOMIC.
This bug is found by my static analysis tool DSAC.
Link: http://lkml.kernel.org/r/20180901112528.27025-1-baijiaju1990@xxxxxxxxx
Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Joseph Qi <jiangqi903@xxxxxxxxx>
Cc: Changwei Ge <ge.changwei@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/dlm/dlmdebug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ocfs2/dlm/dlmdebug.c~fs-ocfs2-dlm-fix-a-sleep-in-atomic-context-bug-in-dlm_print_one_mle
+++ a/fs/ocfs2/dlm/dlmdebug.c
@@ -329,7 +329,7 @@ void dlm_print_one_mle(struct dlm_master
{
char *buf;
- buf = (char *) get_zeroed_page(GFP_NOFS);
+ buf = (char *) get_zeroed_page(GFP_ATOMIC);
if (buf) {
dump_mle(mle, buf, PAGE_SIZE - 1);
free_page((unsigned long)buf);
_
Patches currently in -mm which might be from baijiaju1990@xxxxxxxxx are
fs-ocfs2-dlm-fix-a-sleep-in-atomic-context-bug-in-dlm_print_one_mle.patch
