Message-ID: <688a8cdf.a00a0220.26d0e1.002f.GAE@google.com>
Date: Wed, 30 Jul 2025 14:21:35 -0700
From: syzbot <syzbot+d3fa2fb715cfcc9d201d@...kaller.appspotmail.com>
To: kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] kernel panic: in transaction restart:
 transaction_restart_relock, last restarted by

Hello,

syzbot found the following issue on:

HEAD commit:    4b290aae788e Merge tag 'sysctl-6.17-rc1' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13faeca2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d57eeb4d30293deb
dashboard link: https://syzkaller.appspot.com/bug?extid=d3fa2fb715cfcc9d201d
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-4b290aae.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e5deb700fdcf/vmlinux-4b290aae.xz
kernel image: https://storage.googleapis.com/syzbot-assets/303ba5e224e7/bzImage-4b290aae.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d3fa2fb715cfcc9d201d@...kaller.appspotmail.com

ppp0: PPP: VJ uncompressed error
loop0: detected capacity change from 0 to 32768
bcachefs (loop0): starting version 1.7: mi_btree_bitmap opts=errors=continue,metadata_checksum=none,data_checksum=none,compression=lz4,foreground_target=invalid label 255,nocow
  allowing incompatible features above 0.0: (unknown version)
  features: lz4,new_siphash,inline_data,new_extent_overwrite,btree_ptr_v2,new_varint,journal_no_flush,alloc_v2,extents_across_btree_nodes
bcachefs (loop0): Using encoding defined by superblock: utf8-12.1.0
bcachefs (loop0): initializing new filesystem
bcachefs (loop0): going read-write
bcachefs (loop0): marking superblocks
bcachefs (loop0): initializing freespace
bcachefs (loop0): done initializing freespace
bcachefs (loop0): reading snapshots table
bcachefs (loop0): reading snapshots done
bcachefs (loop0):  loop0: Superblock write was silently dropped! (seq 0 expected 42)
bcachefs (loop0): done starting filesystem
Kernel panic - not syncing: in transaction restart: transaction_restart_relock, last restarted by
[<0>] btree_trans_restart_ip fs/bcachefs/btree_iter.h:364 [inline]
[<0>] btree_trans_restart fs/bcachefs/btree_iter.h:372 [inline]
[<0>] btree_path_get_locks+0x3ad/0xa30 fs/bcachefs/btree_locking.c:491
[<0>] __bch2_trans_relock+0x234/0x5f0 fs/bcachefs/btree_locking.c:826
[<0>] bch2_new_inode fs/bcachefs/fs.c:484 [inline]
[<0>] bch2_inode_hash_init_insert+0x118/0x170 fs/bcachefs/fs.c:501
[<0>] bch2_vfs_inode_get+0x272/0x330 fs/bcachefs/fs.c:524
[<0>] bch2_fs_get_tree+0xfe4/0x1520 fs/bcachefs/fs.c:2572
[<0>] vfs_get_tree+0x8f/0x2b0 fs/super.c:1815
[<0>] do_new_mount+0x2a2/0x9e0 fs/namespace.c:3805
[<0>] do_mount fs/namespace.c:4133 [inline]
[<0>] __do_sys_mount fs/namespace.c:4344 [inline]
[<0>] __se_sys_mount+0x317/0x410 fs/namespace.c:4321
[<0>] do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
[<0>] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
[<0>] entry_SYSCALL_64_after_hwframe+0x77/0x7f
CPU: 0 UID: 0 PID: 5332 Comm: syz.0.0 Not tainted 6.16.0-syzkaller-04405-g4b290aae788e #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x99/0x250 lib/dump_stack.c:120
 panic+0x2db/0x790 kernel/panic.c:442
 bch2_trans_in_restart_error+0xdb/0x110 fs/bcachefs/btree_iter.c:1455
 bch2_trans_put+0x1012/0x1220 fs/bcachefs/btree_iter.c:3559
 bch2_vfs_inode_get+0x285/0x330 fs/bcachefs/fs.c:525
 bch2_fs_get_tree+0xfe4/0x1520 fs/bcachefs/fs.c:2572
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1815
 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3805
 do_mount fs/namespace.c:4133 [inline]
 __do_sys_mount fs/namespace.c:4344 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4321
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f699279014a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6993591e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6993591ef0 RCX: 00007f699279014a
RDX: 00002000000000c0 RSI: 00002000000003c0 RDI: 00007f6993591eb0
RBP: 00002000000000c0 R08: 00007f6993591ef0 R09: 0000000000000810
R10: 0000000000000810 R11: 0000000000000246 R12: 00002000000003c0
R13: 00007f6993591eb0 R14: 0000000000005aa3 R15: 0000200000000040
 </TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..


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