[syzbot] [mm?] general protection fault in vma_merge

syzbot
2023-03-24T05:29:32Z

Hello,

syzbot found the following issue on:

HEAD commit: 7c4a254d78f8 Add linux-next specific files for 20230323
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15230839c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8ba12b2f4a1ff93d
dashboard link: https://syzkaller.appspot.com/bug?extid=29fe1bbf3a023691de49
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c322f39e779d/disk-7c4a254d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bc7ef0a3d51c/vmlinux-7c4a254d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d3f17e539876/bzImage-7c4a254d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+29fe1bbf3a023691de49@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000015: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000a8-0x00000000000000af]
CPU: 0 PID: 5796 Comm: modprobe Not tainted 6.3.0-rc3-next-20230323-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:vma_merge+0x234/0x1fd0 mm/mmap.c:952
Code: 08 00 0f 84 b0 03 00 00 e8 e9 54 bf ff 48 8b 44 24 08 48 8d b8 a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 4d 18 00 00 48 8b 44 24 08 48 8b b0 a8 00 00 00
RSP: 0018:ffffc9000c24fac8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88801cbb2100 RCX: 0000000000000000
RDX: 0000000000000015 RSI: ffffffff81c37957 RDI: 00000000000000a9
RBP: ffff888027fee400 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 00007faf14caa000 R15: ffff88801d2b3400
FS: 00007faf14ca4800(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faf14dd3920 CR3: 0000000078d00000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
mprotect_fixup+0x353/0xbd0 mm/mprotect.c:676
do_mprotect_pkey+0x878/0xd20 mm/mprotect.c:862
__do_sys_mprotect mm/mprotect.c:883 [inline]
__se_sys_mprotect mm/mprotect.c:880 [inline]
__x64_sys_mprotect+0x78/0xb0 mm/mprotect.c:880
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: 0033:0x7faf14fef297
Code: 44 00 00 b8 0b 00 00 00 0f 05 48 3d 01 f0 ff ff 73 01 c3 48 8d 0d 21 1f 01 00 f7 d8 89 01 48 83 c8 ff c3 b8 0a 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8d 0d 01 1f 01 00 f7 d8 89 01 48 83
RSP: 002b:00007ffda9278dc8 EFLAGS: 00000206 ORIG_RAX: 000000000000000a
RAX: ffffffffffffffda RBX: 00007faf14cac000 RCX: 00007faf14fef297
RDX: 0000000000000001 RSI: 0000000000001000 RDI: 00007faf14caa000
RBP: 00007ffda9278ee0 R08: 000000000000ffff R09: 00007faf14dd2d00
R10: 00007faf14caaeb8 R11: 0000000000000206 R12: 00007faf14cac000
R13: 0000000000000007 R14: 0000001700000007 R15: 00007faf14ca75f8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:vma_merge+0x234/0x1fd0 mm/mmap.c:952
Code: 08 00 0f 84 b0 03 00 00 e8 e9 54 bf ff 48 8b 44 24 08 48 8d b8 a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 4d 18 00 00 48 8b 44 24 08 48 8b b0 a8 00 00 00
RSP: 0018:ffffc9000c24fac8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88801cbb2100 RCX: 0000000000000000
RDX: 0000000000000015 RSI: ffffffff81c37957 RDI: 00000000000000a9
RBP: ffff888027fee400 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 00007faf14caa000 R15: ffff88801d2b3400
FS: 00007faf14ca4800(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020004000 CR3: 0000000078d00000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 08 00 or %al,(%rax)
2: 0f 84 b0 03 00 00 je 0x3b8
8: e8 e9 54 bf ff callq 0xffbf54f6
d: 48 8b 44 24 08 mov 0x8(%rsp),%rax
12: 48 8d b8 a8 00 00 00 lea 0xa8(%rax),%rdi
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 4d 18 00 00 jne 0x1881
34: 48 8b 44 24 08 mov 0x8(%rsp),%rax
39: 48 8b b0 a8 00 00 00 mov 0xa8(%rax),%rsi

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