Re: [syzbot] [bcachefs?] UBSAN: shift-out-of-bounds in bch2_stripe_to_text

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
UBSAN: shift-out-of-bounds in bch2_stripe_to_text

bcachefs (loop0): Doing compatible version upgrade from 1.7: mi_btree_bitmap to 1.12: rebalance_work_acct_fix
  running recovery passes: check_allocations
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/bcachefs/ec.c:147:2
shift exponent 108 is too large for 32-bit type 'unsigned int'
CPU: 0 UID: 0 PID: 5588 Comm: syz.0.15 Not tainted 6.11.0-syzkaller-08068-g1ec6d097897a-dirty #0
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 lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468
 bch2_stripe_to_text+0x899/0x8c0 fs/bcachefs/ec.c:147
 __bch2_bkey_fsck_err+0x11f/0x230 fs/bcachefs/error.c:429
 bch2_stripe_validate+0x3ca/0x630 fs/bcachefs/ec.c:116
 bch2_btree_node_read_done+0x3dc6/0x5d60 fs/bcachefs/btree_io.c:1219
 btree_node_read_work+0x68b/0x1260 fs/bcachefs/btree_io.c:1323
 bch2_btree_node_read+0x2433/0x2a10
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1749 [inline]
 bch2_btree_root_read+0x626/0x980 fs/bcachefs/btree_io.c:1773
 read_btree_roots+0x296/0x840 fs/bcachefs/recovery.c:523
 bch2_fs_recovery+0x24ac/0x38b0 fs/bcachefs/recovery.c:851
 bch2_fs_start+0x356/0x5b0 fs/bcachefs/super.c:1036
 bch2_fs_get_tree+0xd61/0x1700 fs/bcachefs/fs.c:1956
 vfs_get_tree+0x90/0x2b0 fs/super.c:1800
 do_new_mount+0x2be/0xb40 fs/namespace.c:3507
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4055 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4032
 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: 0033:0x7f862b97f69a
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:00007f862c6a0e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f862c6a0ef0 RCX: 00007f862b97f69a
RDX: 0000000020005d80 RSI: 0000000020005dc0 RDI: 00007f862c6a0eb0
RBP: 0000000020005d80 R08: 00007f862c6a0ef0 R09: 0000000000200400
R10: 0000000000200400 R11: 0000000000000246 R12: 0000000020005dc0
R13: 00007f862c6a0eb0 R14: 0000000000005da0 R15: 0000000020000340
 </TASK>
---[ end trace ]---


Tested on:

commit:         1ec6d097 Merge tag 's390-6.12-1' of git://git.kernel.o..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=132dbb80580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6265dd30e362bb47
dashboard link: https://syzkaller.appspot.com/bug?extid=f8c98a50c323635be65d
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.