Hello, syzbot found the following issue on: HEAD commit: 95ec54a420b8 Merge tag 'powerpc-6.14-1' of git://git.kerne.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12946964580000 kernel config: https://syzkaller.appspot.com/x/.config?x=161bb0713bee7bb2 dashboard link: https://syzkaller.appspot.com/bug?extid=c41c38d18cb10c84caee compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/ae4f5b920fb2/disk-95ec54a4.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/733fe3f9fdd1/vmlinux-95ec54a4.xz kernel image: https://storage.googleapis.com/syzbot-assets/e1ff7ab4bd3a/bzImage-95ec54a4.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c41c38d18cb10c84caee@xxxxxxxxxxxxxxxxxxxxxxxxx loop3: detected capacity change from 0 to 512 BUG: kernel NULL pointer dereference, address: 0000000000000012 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 800000007ee5d067 P4D 800000007ee5d067 PUD 33cf4067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 UID: 0 PID: 6142 Comm: syz.3.43 Not tainted 6.13.0-syzkaller-00918-g95ec54a420b8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:___slab_alloc+0x595/0x14a0 mm/slub.c:3773 Code: 85 fb 00 00 00 65 4c 8b 2c 25 c0 d4 03 00 4c 89 6b 28 49 83 7e 10 00 0f 85 82 01 00 00 49 8b 5e 18 48 85 db 0f 84 ea 04 00 00 <48> 8b 43 10 49 89 46 18 8b 4c 24 10 83 f9 ff 74 15 48 8b 03 48 83 RSP: 0018:ffffc9000522f6c8 EFLAGS: 00010002 RAX: 7513f5baf7a4fb00 RBX: 0000000000000002 RCX: ffff88802fa9a8d8 RDX: dffffc0000000000 RSI: ffffffff8c0aab60 RDI: ffffffff8c5f49e0 RBP: 0000000000000202 R08: ffffffff9428e887 R09: 1ffffffff2851d10 R10: dffffc0000000000 R11: fffffbfff2851d11 R12: ffff888058f948c0 R13: ffff88802fa99e00 R14: ffffe8ffffd71220 R15: ffffffff81f839cf FS: 00007fa654bc36c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000012 CR3: 000000003348a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __slab_alloc+0x58/0xa0 mm/slub.c:3920 __slab_alloc_node mm/slub.c:3995 [inline] slab_alloc_node mm/slub.c:4156 [inline] kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4175 ext4_mb_add_groupinfo+0x6c3/0xfa0 fs/ext4/mballoc.c:3356 ext4_mb_init_backend fs/ext4/mballoc.c:3435 [inline] ext4_mb_init+0x15ab/0x27e0 fs/ext4/mballoc.c:3733 __ext4_fill_super fs/ext4/super.c:5559 [inline] ext4_fill_super+0x5f54/0x6e60 fs/ext4/super.c:5733 get_tree_bdev_flags+0x48c/0x5c0 fs/super.c:1636 vfs_get_tree+0x90/0x2b0 fs/super.c:1814 do_new_mount+0x2be/0xb40 fs/namespace.c:3560 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088 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: 0033:0x7fa653d874ca 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:00007fa654bc2e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fa654bc2ef0 RCX: 00007fa653d874ca RDX: 0000000020000180 RSI: 0000000020000640 RDI: 00007fa654bc2eb0 RBP: 0000000020000180 R08: 00007fa654bc2ef0 R09: 0000000000000010 R10: 0000000000000010 R11: 0000000000000246 R12: 0000000020000640 R13: 00007fa654bc2eb0 R14: 000000000000047b R15: 0000000020000100 </TASK> Modules linked in: CR2: 0000000000000012 ---[ end trace 0000000000000000 ]--- RIP: 0010:___slab_alloc+0x595/0x14a0 mm/slub.c:3773 Code: 85 fb 00 00 00 65 4c 8b 2c 25 c0 d4 03 00 4c 89 6b 28 49 83 7e 10 00 0f 85 82 01 00 00 49 8b 5e 18 48 85 db 0f 84 ea 04 00 00 <48> 8b 43 10 49 89 46 18 8b 4c 24 10 83 f9 ff 74 15 48 8b 03 48 83 RSP: 0018:ffffc9000522f6c8 EFLAGS: 00010002 RAX: 7513f5baf7a4fb00 RBX: 0000000000000002 RCX: ffff88802fa9a8d8 RDX: dffffc0000000000 RSI: ffffffff8c0aab60 RDI: ffffffff8c5f49e0 RBP: 0000000000000202 R08: ffffffff9428e887 R09: 1ffffffff2851d10 R10: dffffc0000000000 R11: fffffbfff2851d11 R12: ffff888058f948c0 R13: ffff88802fa99e00 R14: ffffe8ffffd71220 R15: ffffffff81f839cf FS: 00007fa654bc36c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000012 CR3: 000000003348a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 85 fb test %edi,%ebx 2: 00 00 add %al,(%rax) 4: 00 65 4c add %ah,0x4c(%rbp) 7: 8b 2c 25 c0 d4 03 00 mov 0x3d4c0,%ebp e: 4c 89 6b 28 mov %r13,0x28(%rbx) 12: 49 83 7e 10 00 cmpq $0x0,0x10(%r14) 17: 0f 85 82 01 00 00 jne 0x19f 1d: 49 8b 5e 18 mov 0x18(%r14),%rbx 21: 48 85 db test %rbx,%rbx 24: 0f 84 ea 04 00 00 je 0x514 * 2a: 48 8b 43 10 mov 0x10(%rbx),%rax <-- trapping instruction 2e: 49 89 46 18 mov %rax,0x18(%r14) 32: 8b 4c 24 10 mov 0x10(%rsp),%ecx 36: 83 f9 ff cmp $0xffffffff,%ecx 39: 74 15 je 0x50 3b: 48 8b 03 mov (%rbx),%rax 3e: 48 rex.W 3f: 83 .byte 0x83 --- 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@xxxxxxxxxxxxxxxx. 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
