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Date:   Tue, 10 Oct 2023 11:18:50 -0700
Message-ID: <0000000000000c44b0060760bd00@google.com>
Subject: [syzbot] [gfs2?] WARNING: suspicious RCU usage in gfs2_permission
From:   syzbot <syzbot+3e5130844b0c0e2b4948@syzkaller.appspotmail.com>
To:     agruenba@redhat.com, gfs2@lists.linux.dev,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        rpeterso@redhat.com, syzkaller-bugs@googlegroups.com
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Hello,

syzbot found the following issue on:

HEAD commit:    7d730f1bf6f3 Add linux-next specific files for 20231005
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11dd3679680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f532286be4fff4b5
dashboard link: https://syzkaller.appspot.com/bug?extid=3e5130844b0c0e2b4948
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1d7f28a4398f/disk-7d730f1b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d454d124268e/vmlinux-7d730f1b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dbca966175cb/bzImage-7d730f1b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3e5130844b0c0e2b4948@syzkaller.appspotmail.com

gfs2: fsid=syz:syz: Now mounting FS (format 1801)...
gfs2: fsid=syz:syz.0: journal 0 mapped with 14 extents in 0ms
gfs2: fsid=syz:syz.0: first mount done, others may mount
=============================
WARNING: suspicious RCU usage
6.6.0-rc4-next-20231005-syzkaller #0 Not tainted
-----------------------------
fs/gfs2/inode.c:1876 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
no locks held by syz-executor.5/5216.

stack backtrace:
CPU: 1 PID: 5216 Comm: syz-executor.5 Not tainted 6.6.0-rc4-next-20231005-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x125/0x1b0 lib/dump_stack.c:106
 lockdep_rcu_suspicious+0x20c/0x3b0 kernel/locking/lockdep.c:6711
 gfs2_permission+0x3f9/0x4c0 fs/gfs2/inode.c:1876
 do_inode_permission fs/namei.c:461 [inline]
 inode_permission fs/namei.c:528 [inline]
 inode_permission+0x384/0x5e0 fs/namei.c:503
 may_open+0x11c/0x400 fs/namei.c:3248
 do_open fs/namei.c:3618 [inline]
 path_openat+0x17aa/0x2ce0 fs/namei.c:3777
 do_filp_open+0x1de/0x430 fs/namei.c:3807
 do_sys_openat2+0x176/0x1e0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f916187b6e0
Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 09 82 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 5c 82 02 00 8b 44
RSP: 002b:00007f916262ce70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007f916187b6e0
RDX: 0000000000010000 RSI: 0000000020000140 RDI: 00000000ffffff9c
RBP: 0000000020000140 R08: 0000000000000000 R09: 0000000000000c19
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000020000140
R13: 00007f916262cf40 R14: 00000000000126ad R15: 00000000200129c0
 </TASK>


---
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