Re: [syzbot] [mm?] [exfat?] [f2fs?] memory leak in __kfree_rcu_sheaf

syzbot
2026-05-04T20:51:03Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel panic: !!! sbi at ADDR used after freeing !!!

F2FS-fs (loop1): f2fs_record_error_work()
Kernel panic - not syncing: !!! sbi at ffff888129322000 used after freeing !!!
CPU: 1 UID: 0 PID: 6598 Comm: kworker/1:5 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events f2fs_record_error_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x97/0xe0 lib/dump_stack.c:120
vpanic+0x383/0x6d0 kernel/panic.c:650
panic+0x6e/0x70 kernel/panic.c:787
f2fs_record_error_work.cold+0x14/0x14 fs/f2fs/super.c:4747
process_one_work+0x277/0x5b0 kernel/workqueue.c:3302
process_scheduled_works kernel/workqueue.c:3385 [inline]
worker_thread+0x255/0x4a0 kernel/workqueue.c:3466
kthread+0x14e/0x1a0 kernel/kthread.c:436
ret_from_fork+0x219/0x490 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Kernel Offset: disabled

Tested on:

commit: 6d35786d Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17a63a36580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9645c21cfd1d3e8f
dashboard link: https://syzkaller.appspot.com/bug?extid=cae7809e9dc1459e4e63
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch: https://syzkaller.appspot.com/x/patch.diff?x=172b8ad2580000