[fs?] general protection fault in do_iter_write

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 011eb7443621 Add linux-next specific files for 20230327
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17e34f75c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8ba12b2f4a1ff93d
dashboard link: https://syzkaller.appspot.com/bug?extid=6db53c36b3d6559c62ed
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [bra...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/513e6a2dc8e5/disk-011eb744.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e1b8a9eee1af/vmlinux-011eb744.xz
kernel image: https://storage.googleapis.com/syzbot-assets/970a4a7123ab/bzImage-011eb744.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6db53c...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0004000298: 0000 [#1] PREEMPT SMP KASAN
KASAN: probably user-memory-access in range [0x00000000200014c0-0x00000000200014c7]
CPU: 1 PID: 8937 Comm: syz-executor.5 Not tainted 6.3.0-rc3-next-20230327-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:iov_iter_iovec include/linux/uio.h:137 [inline]
RIP: 0010:do_loop_readv_writev fs/read_write.c:752 [inline]
RIP: 0010:do_loop_readv_writev fs/read_write.c:743 [inline]
RIP: 0010:do_iter_write+0x482/0x700 fs/read_write.c:863
Code: 00 0f 85 eb 01 00 00 4d 8b 75 28 e8 a8 d9 9e ff 48 8b 44 24 20 80 38 00 0f 85 6b 01 00 00 49 8b 6c 24 18 48 89 ea 48 c1 ea 03 <42> 80 3c 3a 00 0f 85 47 01 00 00 48 8b 44 24 28 48 8b 75 00 80 38
RSP: 0018:ffffc90004d4fc68 EFLAGS: 00010202
RAX: fffff520009a9fae RBX: 0000000000000008 RCX: ffffc9000f783000
RDX: 0000000004000298 RSI: ffffffff81e3fda8 RDI: 0000000000000007
RBP: 00000000200014c0 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000000 R12: ffffc90004d4fd58
R13: ffff88807ad53180 R14: ffffffff8a5cee00 R15: dffffc0000000000
FS: 00007f38c1390700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 00000000223cb000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
vfs_writev+0x1aa/0x670 fs/read_write.c:934
do_writev+0x133/0x2f0 fs/read_write.c:977
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f38c068c0f9
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:00007f38c1390168 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f38c07ac1f0 RCX: 00007f38c068c0f9
RDX: 0000000000000001 RSI: 00000000200017c0 RDI: 0000000000000008
RBP: 00007f38c06e7b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffefa95181f R14: 00007f38c1390300 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:iov_iter_iovec include/linux/uio.h:137 [inline]
RIP: 0010:do_loop_readv_writev fs/read_write.c:752 [inline]
RIP: 0010:do_loop_readv_writev fs/read_write.c:743 [inline]
RIP: 0010:do_iter_write+0x482/0x700 fs/read_write.c:863
Code: 00 0f 85 eb 01 00 00 4d 8b 75 28 e8 a8 d9 9e ff 48 8b 44 24 20 80 38 00 0f 85 6b 01 00 00 49 8b 6c 24 18 48 89 ea 48 c1 ea 03 <42> 80 3c 3a 00 0f 85 47 01 00 00 48 8b 44 24 28 48 8b 75 00 80 38
RSP: 0018:ffffc90004d4fc68 EFLAGS: 00010202
RAX: fffff520009a9fae RBX: 0000000000000008 RCX: ffffc9000f783000
RDX: 0000000004000298 RSI: ffffffff81e3fda8 RDI: 0000000000000007
RBP: 00000000200014c0 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000000 R12: ffffc90004d4fd58
R13: ffff88807ad53180 R14: ffffffff8a5cee00 R15: dffffc0000000000
FS: 00007f38c1390700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 00000000223cb000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 00 0f add %cl,(%rdi)
2: 85 eb test %ebp,%ebx
4: 01 00 add %eax,(%rax)
6: 00 4d 8b add %cl,-0x75(%rbp)
9: 75 28 jne 0x33
b: e8 a8 d9 9e ff callq 0xff9ed9b8
10: 48 8b 44 24 20 mov 0x20(%rsp),%rax
15: 80 38 00 cmpb $0x0,(%rax)
18: 0f 85 6b 01 00 00 jne 0x189
1e: 49 8b 6c 24 18 mov 0x18(%r12),%rbp
23: 48 89 ea mov %rbp,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 42 80 3c 3a 00 cmpb $0x0,(%rdx,%r15,1) <-- trapping instruction
2f: 0f 85 47 01 00 00 jne 0x17c
35: 48 8b 44 24 28 mov 0x28(%rsp),%rax
3a: 48 8b 75 00 mov 0x0(%rbp),%rsi
3e: 80 .byte 0x80
3f: 38 .byte 0x38


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.