linux-kernel - Re: [syzbot] [bcachefs?] UBSAN: shift-out-of-bounds in bch2_btree_node_read

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Message-ID: <000000000000635dec061af5871b@google.com>
Date: Sat, 15 Jun 2024 15:48:20 -0700
From: syzbot <syzbot+e6332ce6aa831184a0eb@...kaller.appspotmail.com>
To: bfoster@...hat.com, kent.overstreet@...ux.dev, 
	linux-bcachefs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bcachefs?] UBSAN: shift-out-of-bounds in bch2_btree_node_read_done

syzbot has found a reproducer for the following issue on:

HEAD commit:    2ccbdf43d5e7 Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17d55446980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b8786f381e62940f
dashboard link: https://syzkaller.appspot.com/bug?extid=e6332ce6aa831184a0eb
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=176f05de980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13f0cbb1980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-2ccbdf43.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c40c1cd990d2/vmlinux-2ccbdf43.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a2a94050804e/bzImage-2ccbdf43.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/7ea194fe115d/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e6332ce6aa831184a0eb@...kaller.appspotmail.com

bcachefs (loop0): mounting version 1.7: mi_btree_bitmap opts=metadata_checksum=none,data_checksum=crc64,background_compression=zstd,str_hash=crc32c,nojournal_transaction_names
bcachefs (loop0): recovering from clean shutdown, journal seq 8
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/bcachefs/btree_types.h:770:13
shift exponent 114 is too large for 32-bit type 'unsigned int'
CPU: 3 PID: 5185 Comm: syz-executor270 Not tainted 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:114
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x2a5/0x480 lib/ubsan.c:468
 btree_node_type_is_extents fs/bcachefs/btree_types.h:770 [inline]
 bch2_btree_node_read_done.cold+0x7a/0x17e fs/bcachefs/btree_io.c:1093
 btree_node_read_work+0x567/0x1060 fs/bcachefs/btree_io.c:1345
 bch2_btree_node_read+0x8b3/0xe40 fs/bcachefs/btree_io.c:1730
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1769 [inline]
 bch2_btree_root_read+0x2ca/0x690 fs/bcachefs/btree_io.c:1793
 read_btree_roots fs/bcachefs/recovery.c:475 [inline]
 bch2_fs_recovery+0x1ba8/0x3db0 fs/bcachefs/recovery.c:803
 bch2_fs_start+0x2e9/0x600 fs/bcachefs/super.c:1035
 bch2_fs_open+0xfa0/0x1110 fs/bcachefs/super.c:2127
 bch2_mount+0xe2c/0x1230 fs/bcachefs/fs.c:1919
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1780
 do_new_mount fs/namespace.c:3352 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount fs/namespace.c:3875 [inline]
 __x64_sys_mount+0x297/0x320 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fac2a06097a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffed16b1868 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffed16b1880 RCX: 00007fac2a06097a
RDX: 0000000020005b00 RSI: 0000000020000040 RDI: 00007ffed16b1880
RBP: 0000000000000004 R08: 00007ffed16b18c0 R09: 0000000000005b2d
R10: 0000000000018080 R11: 0000000000000282 R12: 0000000000018080
R13: 00007ffed16b18c0 R14: 0000000000000003 R15: 0000000001000000
 </TASK>
---[ end trace ]---


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.