[syzbot] [raid?] UBSAN: array-index-out-of-bounds in super_90_sync
From: syzbot <hidden>
Date: 2026-09-13 13:09:38
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Hello, syzbot found the following issue on: HEAD commit: 893e11787f78 Merge tag 'x86_urgent_for_7.3-rc3' of git://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11af7af9580000 kernel config: https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f dashboard link: https://syzkaller.appspot.com/bug?extid=9e3014263a35700ab49b compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/7d6d05cecce7/disk-893e1178.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/f4fa34852d36/vmlinux-893e1178.xz kernel image: https://storage.googleapis.com/syzbot-assets/5a45af623528/bzImage-893e1178.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9e3014263a35700ab49b@syzkaller.appspotmail.com md: async del_gendisk mode will be removed in future, please upgrade to mdadm-4.5+ ------------[ cut here ]------------ UBSAN: array-index-out-of-bounds in drivers/md/md.c:1697:17 index 124 is out of range for type 'mdp_disk_t [27]' CPU: 1 UID: 0 PID: 10197 Comm: syz.3.1362 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233 __ubsan_handle_out_of_bounds+0xcc/0xf0 lib/ubsan.c:455 super_90_sync+0x1eed/0x1ff0 drivers/md/md.c:1697 sync_super drivers/md/md.c:2505 [inline] sync_sbs drivers/md/md.c:2747 [inline] md_update_sb+0xbba/0x2840 drivers/md/md.c:2923 state_store+0x31e/0x1340 drivers/md/md.c:3245 rdev_attr_store+0x465/0x560 drivers/md/md.c:3768 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6af/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f977e59e159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f977f3cb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f977e825fa0 RCX: 00007f977e59e159 RDX: 000000000000000b RSI: 0000200000000a00 RDI: 0000000000000006 RBP: 00007f977e63503b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f977e826038 R14: 00007f977e825fa0 R15: 00007ffef91f5d68 </TASK> ---[ end trace ]--- --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup