[syzbot] [bcachefs?] UBSAN: shift-out-of-bounds in __bch2_btree_node_hash_insert

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    8155b4ef3466 Add linux-next specific files for 20241220
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=113ffadf980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9c90bb7161a56c88
dashboard link: https://syzkaller.appspot.com/bug?extid=029d1989099aa5ae3e89
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10bcd2c4580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=155d8af8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98a974fc662d/disk-8155b4ef.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2dea9b72f624/vmlinux-8155b4ef.xz
kernel image: https://storage.googleapis.com/syzbot-assets/593a42b9eb34/bzImage-8155b4ef.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f6dde2a7f3a7/mount_0.gz

The issue was bisected to:

commit 46522a75a47ed8db6da54f37c4dcf934e12fe540
Author: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Date:   Mon Nov 25 05:21:27 2024 +0000

    bcachefs: Bad btree roots are now autofix

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15e2caf8580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=17e2caf8580000
console output: https://syzkaller.appspot.com/x/log.txt?x=13e2caf8580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+029d1989099aa5ae3e89@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 46522a75a47e ("bcachefs: Bad btree roots are now autofix")

bcachefs (loop0): running explicit recovery pass check_backpointers_to_extents (16), currently at recovery_pass_empty (0)
bcachefs (loop0): running explicit recovery pass scan_for_btree_nodes (1), currently at recovery_pass_empty (0)
error reading btree root btree=xattrs level=0: btree_node_read_error, fixing
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/bcachefs/btree_cache.c:215:18
shift exponent 251 is too large for 64-bit type 'unsigned long long'
CPU: 0 UID: 0 PID: 5833 Comm: syz-executor472 Not tainted 6.13.0-rc3-next-20241220-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468
 __btree_node_pinned fs/bcachefs/btree_cache.c:215 [inline]
 __bch2_btree_node_hash_insert+0x1b1d/0x1b80 fs/bcachefs/btree_cache.c:291
 bch2_btree_node_hash_insert+0x7e/0xc0 fs/bcachefs/btree_cache.c:306
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1783 [inline]
 bch2_btree_root_read+0x5c6/0x7a0 fs/bcachefs/btree_io.c:1811
 read_btree_roots+0x375/0x9e0 fs/bcachefs/recovery.c:582
 bch2_fs_recovery+0x260f/0x3de0 fs/bcachefs/recovery.c:929
 bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1032
 bch2_fs_get_tree+0xd8d/0x1740 fs/bcachefs/fs.c:2200
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3556
 do_mount fs/namespace.c:3896 [inline]
 __do_sys_mount fs/namespace.c:4107 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4084
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f15c224ca4a
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:00007ffd1e726af8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd1e726b10 RCX: 00007f15c224ca4a
RDX: 0000000020000180 RSI: 0000000020000540 RDI: 00007ffd1e726b10
RBP: 0000000000000004 R08: 00007ffd1e726b50 R09: 0000000000005964
R10: 0000000000800000 R11: 0000000000000282 R12: 0000000000800000
R13: 00007ffd1e726b50 R14: 0000000000000003 R15: 0000000001000000
 </TASK>
---[ end trace ]---


---
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