On 7/13/24 9:24 AM, syzbot wrote:
Hello,
syzbot found the following issue on:
HEAD commit: 8b9b59e27aa8 i40e: fix: remove needless retries of NVM upd..
git tree: bpf
console+strace: https://syzkaller.appspot.com/x/log.txt?x=135ee4f6980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b63b35269462a0e0
dashboard link: https://syzkaller.appspot.com/bug?extid=ad9ec60c8eaf69e6f99c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=171399dd980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e4054e980000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/535b0bcd3e1f/disk-8b9b59e2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/127f5ddff150/vmlinux-8b9b59e2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a3ac9910529c/bzImage-8b9b59e2.xz
The issue was bisected to:
commit 1f1e864b65554e33fe74e3377e58b12f4302f2eb
Author: Yonghong Song <yonghong.song@xxxxxxxxx>
Date: Fri Jul 28 01:12:07 2023 +0000
bpf: Handle sign-extenstin ctx member accesses
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=121c054e980000
final oops: https://syzkaller.appspot.com/x/report.txt?x=111c054e980000
console output: https://syzkaller.appspot.com/x/log.txt?x=161c054e980000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ad9ec60c8eaf69e6f99c@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 1f1e864b6555 ("bpf: Handle sign-extenstin ctx member accesses")
BUG: unable to handle page fault for address: 000000002aebd040
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 80000000226b6067 P4D 80000000226b6067 PUD 226b7067 PMD 0
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 PID: 5096 Comm: syz-executor365 Not tainted 6.10.0-rc7-syzkaller-00133-g8b9b59e27aa8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:bpf_prog_82ec301e76077160+0x5c/0xa0
Code: 0a b8 02 00 00 00 41 5d 5b c9 c3 48 89 df 48 8b b7 d8 00 00 00 48 63 f6 48 8b 57 50 48 89 f0 48 83 c0 08 48 39 c2 77 02 eb dc <48> 0f b7 5e 00 4c 0f bf eb 48 81 fb 0f ff 07 00 74 00 48 c1 e3 20
RSP: 0018:ffffc900031f7980 EFLAGS: 00010292
RAX: 000000002aebd048 RBX: 0000000000000000 RCX: ffff888076a99e00
RDX: ffff88802aebd050 RSI: 000000002aebd040 RDI: ffff8880226b4b40
RBP: ffffc900031f7990 R08: ffffffff8183cf51 R09: 1ffffffff1f5b295
R10: dffffc0000000000 R11: ffffffffa0001f9c R12: ffffffff8998404e
R13: dffffc0000000000 R14: ffffc90000ace030 R15: ffffc90000ace020
FS: 0000555562a39380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002aebd040 CR3: 0000000021bc0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
__bpf_prog_run include/linux/filter.h:691 [inline]
bpf_prog_run include/linux/filter.h:698 [inline]
bpf_test_run+0x409/0x910 net/bpf/test_run.c:425
bpf_prog_test_run_skb+0xafa/0x13a0 net/bpf/test_run.c:1072
bpf_prog_test_run+0x33a/0x3b0 kernel/bpf/syscall.c:4292
__sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5706
__do_sys_bpf kernel/bpf/syscall.c:5795 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5793 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5793
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: 0033:0x7fcd7dc9bbb9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 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:00007ffc1893ff98 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcd7dc9bbb9
RDX: 000000000000004c RSI: 0000000020000240 RDI: 000000000000000a
RBP: 0000000000000000 R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
</TASK>
Modules linked in:
CR2: 000000002aebd040
---[ end trace 0000000000000000 ]---
RIP: 0010:bpf_prog_82ec301e76077160+0x5c/0xa0
Code: 0a b8 02 00 00 00 41 5d 5b c9 c3 48 89 df 48 8b b7 d8 00 00 00 48 63 f6 48 8b 57 50 48 89 f0 48 83 c0 08 48 39 c2 77 02 eb dc <48> 0f b7 5e 00 4c 0f bf eb 48 81 fb 0f ff 07 00 74 00 48 c1 e3 20
RSP: 0018:ffffc900031f7980 EFLAGS: 00010292
RAX: 000000002aebd048 RBX: 0000000000000000 RCX: ffff888076a99e00
RDX: ffff88802aebd050 RSI: 000000002aebd040 RDI: ffff8880226b4b40
RBP: ffffc900031f7990 R08: ffffffff8183cf51 R09: 1ffffffff1f5b295
R10: dffffc0000000000 R11: ffffffffa0001f9c R12: ffffffff8998404e
R13: dffffc0000000000 R14: ffffc90000ace030 R15: ffffc90000ace020
FS: 0000555562a39380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002aebd040 CR3: 0000000021bc0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 0a b8 02 00 00 00 or 0x2(%rax),%bh
6: 41 5d pop %r13
8: 5b pop %rbx
9: c9 leave
a: c3 ret
b: 48 89 df mov %rbx,%rdi
e: 48 8b b7 d8 00 00 00 mov 0xd8(%rdi),%rsi
15: 48 63 f6 movslq %esi,%rsi
18: 48 8b 57 50 mov 0x50(%rdi),%rdx
1c: 48 89 f0 mov %rsi,%rax
1f: 48 83 c0 08 add $0x8,%rax
23: 48 39 c2 cmp %rax,%rdx
26: 77 02 ja 0x2a
28: eb dc jmp 0x6
* 2a: 48 0f b7 5e 00 movzwq 0x0(%rsi),%rbx <-- trapping instruction
2f: 4c 0f bf eb movswq %bx,%r13
33: 48 81 fb 0f ff 07 00 cmp $0x7ff0f,%rbx
3a: 74 00 je 0x3c
3c: 48 c1 e3 20 shl $0x20,%rbx
---
This report is generated by a bot. It may contain errors.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
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#syz fix: exact-commit-title
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The failure is due to the following bpf code:
r2 = *(s32 *)(r1 + 76) /* __sk_buff->data */
r3 = *(u32 *)(r1 + 80) /* __sk_buff->data_end */
r0 = r2
r0 += 8
if r3 > r0 goto +1
After verification:
r2 = *(u64 *)(r1 +208)
r2 = (s32)r2 /* added in convert_ctx_accesses() */
r3 = *(u64 *)(r1 +80)
r0 = r2
r0 += 8
if r3 > r0 goto pc+1
The 'r2 = (s32)r2' will cause incorrect __sk_buff->data.
I will send a patch shortly.
