From 345e0e270234d6eda34837bd6a93b95b8d8846cc Mon Sep 17 00:00:00 2001 From: Jia-Ju Bai Date: Fri, 26 Oct 2018 15:02:52 -0700 Subject: fs/ocfs2/dlm/dlmdebug.c: fix a sleep-in-atomic-context bug in dlm_print_one_mle() [ Upstream commit 999865764f5f128896402572b439269acb471022 ] 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@gmail.com Signed-off-by: Jia-Ju Bai Reviewed-by: Andrew Morton Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Joseph Qi Cc: Changwei Ge Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- fs/ocfs2/dlm/dlmdebug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ocfs2/dlm/dlmdebug.c') diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c index e7b760deefae..32d60f69db24 100644 --- a/fs/ocfs2/dlm/dlmdebug.c +++ b/fs/ocfs2/dlm/dlmdebug.c @@ -329,7 +329,7 @@ void dlm_print_one_mle(struct dlm_master_list_entry *mle) { 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); -- cgit v1.2.3