ff84772fd4
There is a potential deadlock reported by syzbot as below:
======================================================
WARNING: possible circular locking dependency detected
6.4.0-next-20230707-syzkaller #0 Not tainted
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syz-executor330/5073 is trying to acquire lock:
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable include/linux/mmap_lock.h:151 [inline]
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5293 [inline]
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x369/0x510 mm/memory.c:5344
but task is already holding lock:
ffff888019f760e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_iterate+0x117/0xb50 fs/exfat/dir.c:232
which lock already depends on the new lock.
Chain exists of:
&mm->mmap_lock --> mapping.invalidate_lock#3 --> &sbi->s_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sbi->s_lock);
lock(mapping.invalidate_lock#3);
lock(&sbi->s_lock);
rlock(&mm->mmap_lock);
Let's try to avoid above potential deadlock condition by moving dir_emit*()
out of sbi->s_lock coverage.
Fixes:
|
||
|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| balloc.c | ||
| cache.c | ||
| dir.c | ||
| exfat_fs.h | ||
| exfat_raw.h | ||
| fatent.c | ||
| file.c | ||
| inode.c | ||
| misc.c | ||
| namei.c | ||
| nls.c | ||
| super.c | ||