linux-kernel - Re: [syzbot] [bcachefs?] KASAN: slab-out-of-bounds Read in __bch2_bkey_unpack

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Message-ID: <67cb2ca1.050a0220.15b4b9.0084.GAE@google.com>
Date: Fri, 07 Mar 2025 09:28:01 -0800
From: syzbot <syzbot+b9d9de2aa46b1bbe575a@...kaller.appspotmail.com>
To: kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, mmpgouride@...il.com, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bcachefs?] KASAN: slab-out-of-bounds Read in __bch2_bkey_unpack_key

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in bch2_trans_put

------------[ cut here ]------------
btree trans held srcu lock (delaying memory reclaim) for 11 seconds
WARNING: CPU: 0 PID: 37 at fs/bcachefs/btree_iter.c:3202 check_srcu_held_too_long fs/bcachefs/btree_iter.c:3200 [inline]
WARNING: CPU: 0 PID: 37 at fs/bcachefs/btree_iter.c:3202 bch2_trans_put+0xe36/0x1020 fs/bcachefs/btree_iter.c:3457
Modules linked in:
CPU: 0 UID: 0 PID: 37 Comm: kworker/0:1H Not tainted 6.14.0-rc1-syzkaller-g47e4e14a59ec #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: bcachefs_btree_io btree_node_write_work
RIP: 0010:check_srcu_held_too_long fs/bcachefs/btree_iter.c:3200 [inline]
RIP: 0010:bch2_trans_put+0xe36/0x1020 fs/bcachefs/btree_iter.c:3457
Code: 1c 24 48 c1 eb 02 48 b9 c3 f5 28 5c 8f c2 f5 28 48 89 d8 48 f7 e1 48 c1 ea 02 48 c7 c7 40 3f 72 8c 48 89 d6 e8 6b 71 32 fd 90 <0f> 0b 90 90 e9 63 f8 ff ff e8 fc a9 72 fd 90 0f 0b 90 e9 a6 f8 ff
RSP: 0018:ffffc90000587910 EFLAGS: 00010246
RAX: f68e1852cb63db00 RBX: 0000000000000121 RCX: ffff88801e220000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00000000ffffce37 R08: ffffffff81817d12 R09: 1ffff11003f8519a
R10: dffffc0000000000 R11: ffffed1003f8519b R12: ffff88804f04c088
R13: 1ffff11009e09811 R14: ffff88804f04c042 R15: 1ffff11009e09808
FS:  0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd96e77d538 CR3: 0000000012314000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 btree_node_write_work+0xa91/0xbb0 fs/bcachefs/btree_io.c:2098
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>


Tested on:

commit:         47e4e14a bcachefs: Fix b->written overflow
git tree:       https://github.com/alanskind/bcachefs
console output: https://syzkaller.appspot.com/x/log.txt?x=16b843a8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9a4389e017863e2
dashboard link: https://syzkaller.appspot.com/bug?extid=b9d9de2aa46b1bbe575a
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.