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UBSAN: shift-out-of-bounds in read_one_super (2)

Status: fixed on 2024/07/09 19:14
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+9f74cb4006b83e2a3df1@syzkaller.appspotmail.com
Fix commit: d406545613b5 bcachefs: Fix shift overflow in read_one_super()
First crash: 117d, last: 116d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] UBSAN: shift-out-of-bounds in read_one_super (2) 1 (2) 2024/06/17 13:21
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream UBSAN: shift-out-of-bounds in read_one_super bcachefs C done 31 126d 155d 25/28 fixed on 2024/06/05 13:52

Sample crash report:
loop2: detected capacity change from 0 to 32789
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/bcachefs/super-io.c:653:3
shift exponent 106 is too large for 64-bit type 'unsigned long'
CPU: 0 PID: 9174 Comm: syz-executor.2 Not tainted 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468
 read_one_super+0xfb5/0xfc0 fs/bcachefs/super-io.c:653
 __bch2_read_super+0x65a/0x1460 fs/bcachefs/super-io.c:750
 bch2_fs_open+0x246/0xdf0 fs/bcachefs/super.c:2074
 bch2_mount+0x6b0/0x13a0 fs/bcachefs/fs.c:1919
 legacy_get_tree+0xf0/0x190 fs/fs_context.c:662
 vfs_get_tree+0x92/0x2a0 fs/super.c:1780
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
 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: 0033:0x7f82b087e5aa
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f82b1586ef8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f82b1586f80 RCX: 00007f82b087e5aa
RDX: 0000000020011a00 RSI: 0000000020000780 RDI: 00007f82b1586f40
RBP: 0000000020011a00 R08: 00007f82b1586f80 R09: 0000000001200014
R10: 0000000001200014 R11: 0000000000000206 R12: 0000000020000780
R13: 00007f82b1586f40 R14: 00000000000119fa R15: 00000000200007c0
 </TASK>
---[ end trace ]---

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/13 21:46 upstream 2ccbdf43d5e7 a9616ff5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root UBSAN: shift-out-of-bounds in read_one_super
2024/06/13 11:04 upstream cea2a26553ac 2aa5052f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root UBSAN: shift-out-of-bounds in read_one_super
2024/06/13 10:08 upstream cea2a26553ac 2aa5052f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root UBSAN: shift-out-of-bounds in read_one_super
2024/06/13 08:56 upstream cea2a26553ac 2aa5052f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root UBSAN: shift-out-of-bounds in read_one_super
* Struck through repros no longer work on HEAD.