On Wed, Dec 28, 2022 at 10:40 PM syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 51094a24b85e Merge tag 'hardening-v6.2-rc1-fixes' of git:/.. > git tree: upstream > console+strace: https://syzkaller.appspot.com/x/log.txt?x=172e2b44480000 > kernel config: https://syzkaller.appspot.com/x/.config?x=4e2d7bfa2d6d5a76 > dashboard link: https://syzkaller.appspot.com/bug?extid=ede796cecd5296353515 > compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1243578c480000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1506f1ac480000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/a26f3769fdfb/disk-51094a24.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/5decc3ae71d7/vmlinux-51094a24.xz > kernel image: https://storage.googleapis.com/syzbot-assets/dd2ac18a5b04/bzImage-51094a24.xz > mounted in repro: https://storage.googleapis.com/syzbot-assets/559169c47ec8/mount_0.gz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+ede796cecd5296353515@xxxxxxxxxxxxxxxxxxxxxxxxx > > loop0: detected capacity change from 0 to 2048 > general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] > CPU: 1 PID: 5066 Comm: syz-executor153 Not tainted 6.1.0-syzkaller-14587-g51094a24b85e #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 > RIP: 0010:nilfs_btree_get_nonroot_node fs/nilfs2/btree.c:418 [inline] > RIP: 0010:nilfs_btree_prepare_insert fs/nilfs2/btree.c:1077 [inline] > RIP: 0010:nilfs_btree_insert+0x6d3/0x1c10 fs/nilfs2/btree.c:1238 > Code: bc 24 80 00 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 4b 02 92 fe 4d 8b 3f 49 83 c7 28 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 2e 02 92 fe 4d 8b 3f 49 83 c7 02 > RSP: 0018:ffffc90003bcf4a0 EFLAGS: 00010206 > RAX: 0000000000000005 RBX: 0000000000000001 RCX: 0000000000000000 > RDX: ffff88807eba3a80 RSI: 0000000000000002 RDI: 0000000000000001 > RBP: ffffc90003bcf630 R08: ffffffff834f80d8 R09: ffffed100571ff9b > R10: ffffed100571ff9b R11: 1ffff1100571ff9a R12: ffff888021d03480 > R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000028 > FS: 000055555588c300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f4614ff5a70 CR3: 000000007eb7c000 CR4: 00000000003506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > nilfs_bmap_do_insert fs/nilfs2/bmap.c:121 [inline] > nilfs_bmap_insert+0x20d/0x360 fs/nilfs2/bmap.c:147 > nilfs_get_block+0x414/0x8d0 fs/nilfs2/inode.c:101 > __block_write_begin_int+0x54c/0x1a80 fs/buffer.c:1991 > __block_write_begin fs/buffer.c:2041 [inline] > block_write_begin+0x93/0x1e0 fs/buffer.c:2102 > nilfs_write_begin+0x9c/0x110 fs/nilfs2/inode.c:261 > generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772 > __generic_file_write_iter+0x176/0x400 mm/filemap.c:3900 > generic_file_write_iter+0xab/0x310 mm/filemap.c:3932 > call_write_iter include/linux/fs.h:2186 [inline] > new_sync_write fs/read_write.c:491 [inline] > vfs_write+0x7dc/0xc50 fs/read_write.c:584 > ksys_write+0x177/0x2a0 fs/read_write.c:637 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7fca03d80b59 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007ffdd1df8c28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fca03d80b59 > RDX: 000000000000002f RSI: 0000000020000040 RDI: 0000000000000004 > RBP: 00007fca03d40160 R08: 0000000000000014 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fca03d401f0 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:nilfs_btree_get_nonroot_node fs/nilfs2/btree.c:418 [inline] > RIP: 0010:nilfs_btree_prepare_insert fs/nilfs2/btree.c:1077 [inline] > RIP: 0010:nilfs_btree_insert+0x6d3/0x1c10 fs/nilfs2/btree.c:1238 > Code: bc 24 80 00 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 4b 02 92 fe 4d 8b 3f 49 83 c7 28 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 2e 02 92 fe 4d 8b 3f 49 83 c7 02 > RSP: 0018:ffffc90003bcf4a0 EFLAGS: 00010206 > RAX: 0000000000000005 RBX: 0000000000000001 RCX: 0000000000000000 > RDX: ffff88807eba3a80 RSI: 0000000000000002 RDI: 0000000000000001 > RBP: ffffc90003bcf630 R08: ffffffff834f80d8 R09: ffffed100571ff9b > R10: ffffed100571ff9b R11: 1ffff1100571ff9a R12: ffff888021d03480 > R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000028 > FS: 000055555588c300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000055a236e64fe0 CR3: 000000007eb7c000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: bc 24 80 00 00 mov $0x8024,%esp > 5: 00 4c 89 f8 add %cl,-0x8(%rcx,%rcx,4) > 9: 48 c1 e8 03 shr $0x3,%rax > d: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) > 12: 74 08 je 0x1c > 14: 4c 89 ff mov %r15,%rdi > 17: e8 4b 02 92 fe callq 0xfe920267 > 1c: 4d 8b 3f mov (%r15),%r15 > 1f: 49 83 c7 28 add $0x28,%r15 > 23: 4c 89 f8 mov %r15,%rax > 26: 48 c1 e8 03 shr $0x3,%rax > * 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction > 2f: 74 08 je 0x39 > 31: 4c 89 ff mov %r15,%rdi > 34: e8 2e 02 92 fe callq 0xfe920267 > 39: 4d 8b 3f mov (%r15),%r15 > 3c: 49 83 c7 02 add $0x2,%r15 > > > --- > 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. > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches This seems to be an unfixed bug in nilfs2. As a result of analysis using the C-reproducer, it turns out that nilfs_btree_insert() may cause the above oops when nilfs2 reads a corrupted disk image and a b-tree node block address translation fails due to a DAT metadata corruption. It's necessary to correct the error handling in the above case. I'll take a closer look to fix this. Ryusuke Konishi
