Messages in this thread Patch in this message | | | From | Jia-Ju Bai <> | Subject | [PATCH] fs/afs/flock and fs/locks: Fix possible sleep-in-atomic bugs in posix_lock_file | Date | Sat, 7 Oct 2017 17:55:04 +0800 |
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The kernel may sleep under a spinlock, and the function call paths are: afs_do_unlk (acquire the spinlock) posix_lock_file posix_lock_inode (fs/locks.c) locks_get_lock_context kmem_cache_alloc(GFP_KERNEL) --> may sleep
afs_do_setlk (acquire the spinlock) posix_lock_file posix_lock_inode (fs/locks.c) locks_get_lock_context kmem_cache_alloc(GFP_KERNEL) --> may sleep
To fix them, GFP_KERNEL is replaced with GFP_ATOMIC. These bugs are found by my static analysis tool and my code review.
Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com> --- fs/locks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/locks.c b/fs/locks.c index 1bd71c4..975cc62 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -222,7 +222,7 @@ struct file_lock_list_struct { if (likely(ctx) || type == F_UNLCK) goto out; - ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL); + ctx = kmem_cache_alloc(flctx_cache, GFP_ATOMIC); if (!ctx) goto out; -- 1.7.9.5
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