syzbot


BUG: unable to handle kernel NULL pointer dereference in nilfs_segctor_do_construct

Status: upstream: reported on 2022/11/16 10:39
Subsystems: nilfs (incorrect?)
Reported-by: syzbot+5afc832d6dbb2fd17538@syzkaller.appspotmail.com
First crash: 137d, last: 36d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 general protection fault in nilfs_segctor_do_construct C 1 37d 149d 0/1 upstream: reported C repro on 2022/10/30 19:35

Sample crash report:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 27631067 P4D 27631067 PUD 2b68d067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7859 Comm: syz-executor.2 Not tainted 6.2.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90016a16cb8 EFLAGS: 00010246
RAX: 0000000000000020 RBX: 0000000000000000 RCX: ffffffff8b258b20
RDX: ffffc90016a17020 RSI: ffffc90016a17000 RDI: ffff88807a797800
RBP: ffffc90016a171f0 R08: ffffffff83527cfd R09: ffffed100ec20e47
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000041
R13: dffffc0000000000 R14: ffffc90016a17001 R15: 0000000000000001
FS:  00007ff917e01700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000770c6000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 nilfs_segctor_assign fs/nilfs2/segment.c:1629 [inline]
 nilfs_segctor_do_construct+0x3c63/0x6f70 fs/nilfs2/segment.c:2056
 nilfs_construct_dsync_segment+0x5c4/0x6c0 fs/nilfs2/segment.c:2310
 do_writepages+0x3a6/0x670 mm/page-writeback.c:2581
 filemap_fdatawrite_wbc+0x125/0x180 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 filemap_write_and_wait_range+0x1d4/0x2c0 mm/filemap.c:674
 __generic_file_write_iter+0x2c8/0x400 mm/filemap.c:3887
 generic_file_write_iter+0xaf/0x310 mm/filemap.c:3933
 do_iter_write+0x6ea/0xc50 fs/read_write.c:861
 iter_file_splice_write+0x80a/0xfa0 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0xe7/0x1c0 fs/splice.c:931
 splice_direct_to_actor+0x4c4/0xbd0 fs/splice.c:886
 do_splice_direct+0x283/0x3d0 fs/splice.c:974
 do_sendfile+0x620/0xff0 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1323 [inline]
 __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1309
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7ff91708c0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff917e01168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007ff9171abf80 RCX: 00007ff91708c0f9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000006
RBP: 00007ff9170e7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 7fffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffae0ac9ff R14: 00007ff917e01300 R15: 0000000000022000
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90016a16cb8 EFLAGS: 00010246
RAX: 0000000000000020 RBX: 0000000000000000 RCX: ffffffff8b258b20
RDX: ffffc90016a17020 RSI: ffffc90016a17000 RDI: ffff88807a797800
RBP: ffffc90016a171f0 R08: ffffffff83527cfd R09: ffffed100ec20e47
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000041
R13: dffffc0000000000 R14: ffffc90016a17001 R15: 0000000000000001
FS:  00007ff917e01700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000770c6000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-upstream-fs 2023/02/20 11:35 upstream c9c3395d5e3d bcdf85f8 .config console log report info [disk image] [vmlinux] [kernel image] BUG: unable to handle kernel NULL pointer dereference in nilfs_segctor_do_construct
ci-upstream-gce-arm64 2022/11/12 05:40 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 1621b6eaebf7 3ead01ad .config console log report info [disk image] [vmlinux] [kernel image] BUG: unable to handle kernel NULL pointer dereference in nilfs_segctor_do_construct
* Struck through repros no longer work on HEAD.