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AKwUvBzVg+TvQQoAovUYv+0smtu+Ck3OnGMip0EWvxrMRe8YGFudN+LM3Hpa4AsKRhhCkvY0Qb6VspLiA+qGHJw=@vger.kernel.org X-Gm-Message-State: AFuF++ntmrwD58bOxp0YHShxcpjSn6J03mqHgTQnS/+R2OtAZIhhltV0 tofO5KlCGQ+SkU6NO2wyC3xGGcXp7OMgg1cg2ql3QbWaiP1+XhG9DrWNvTWyy2No3kZo/R9rBU8 EUNpOWgjU5Qx61Lfla6o/NOfrwYiYuKkF8X2hychAv8l7khlzUKtbRksaWu4= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:610:b0:6be:2c0f:e40b with SMTP id 006d021491bc7-6c53f15bc1fmr2698790eaf.2.1789423889684; Mon, 14 Sep 2026 15:11:29 -0700 (PDT) Date: Mon, 14 Sep 2026 15:11:29 -0700 In-Reply-To: <6a6ecd0c.6ce73036.24301b.001c.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6aa87111.f81106d8.2ab401.0057.GAE@google.com> Subject: Re: [syzbot] [kernel?] BUG: unable to handle kernel paging request in write_comp_data From: syzbot To: boqun@kernel.org, linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, paulmck@kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 704340f1cd0d Merge tag 'x86_urgent_for_7.3-rc4' of git://g.. git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=13351925580000 kernel config: https://syzkaller.appspot.com/x/.config?x=8c5c3949d762a91f dashboard link: https://syzkaller.appspot.com/bug?extid=237f670105a254a230d4 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11b875f9580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+237f670105a254a230d4@syzkaller.appspotmail.com BUG: unable to handle page fault for address: ffffc90003792fe8 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 1c000067 P4D 1c000067 PUD 1d695067 PMD 25aa1067 PTE 0 Oops: Oops: 0002 [#1] SMP KASAN NOPTI CPU: 2 UID: 0 PID: 6034 Comm: syz-executor404 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:write_comp_data+0x7c/0xa0 kernel/kcov.c:263 Code: 00 8b bf 14 17 00 00 48 8b 30 48 c1 e7 03 4c 8d 1c b5 00 00 00 00 4a 8d 14 dd 28 00 00 00 48 39 d7 72 1b 48 83 c6 01 48 89 30 <4c> 89 44 10 e0 4c 89 4c 10 e8 4c 89 54 10 f0 4a 89 4c d8 20 e9 9b RSP: 0018:ffffc900016cfec0 EFLAGS: 00010257 RAX: ffffc90003793000 RBX: 0000000000000000 RCX: ffffffff824af562 RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000002000 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: fffffffffffffffc R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 000055556039d400(0000) GS:ffff8880d5d59000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc90003792fe8 CR3: 0000000033822000 CR4: 0000000000352ef0 Call Trace: __do_sys_rseq kernel/rseq.c:549 [inline] __se_sys_rseq kernel/rseq.c:547 [inline] __x64_sys_rseq+0xc2/0x2e0 kernel/rseq.c:547 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4f6e875649 Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 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 d8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fffe975f1b8 EFLAGS: 00000246 ORIG_RAX: 000000000000014e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4f6e875649 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f4f6e846000 R08: 0000000000000000 R09: 00000000000a8ca8 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffe975f2e8 R13: 0000000000000002 R14: 00007f4f6e8f8cc0 R15: 0000000000000002 Modules linked in: CR2: ffffc90003792fe8 ---[ end trace 0000000000000000 ]--- RIP: 0010:write_comp_data+0x7c/0xa0 kernel/kcov.c:263 Code: 00 8b bf 14 17 00 00 48 8b 30 48 c1 e7 03 4c 8d 1c b5 00 00 00 00 4a 8d 14 dd 28 00 00 00 48 39 d7 72 1b 48 83 c6 01 48 89 30 <4c> 89 44 10 e0 4c 89 4c 10 e8 4c 89 54 10 f0 4a 89 4c d8 20 e9 9b RSP: 0018:ffffc900016cfec0 EFLAGS: 00010257 RAX: ffffc90003793000 RBX: 0000000000000000 RCX: ffffffff824af562 RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000002000 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: fffffffffffffffc R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 000055556039d400(0000) GS:ffff8880d5d59000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc90003792fe8 CR3: 0000000033822000 CR4: 0000000000352ef0 ---------------- Code disassembly (best guess): 0: 00 8b bf 14 17 00 add %cl,0x1714bf(%rbx) 6: 00 48 8b add %cl,-0x75(%rax) 9: 30 48 c1 xor %cl,-0x3f(%rax) c: e7 03 out %eax,$0x3 e: 4c 8d 1c b5 00 00 00 lea 0x0(,%rsi,4),%r11 15: 00 16: 4a 8d 14 dd 28 00 00 lea 0x28(,%r11,8),%rdx 1d: 00 1e: 48 39 d7 cmp %rdx,%rdi 21: 72 1b jb 0x3e 23: 48 83 c6 01 add $0x1,%rsi 27: 48 89 30 mov %rsi,(%rax) * 2a: 4c 89 44 10 e0 mov %r8,-0x20(%rax,%rdx,1) <-- trapping instruction 2f: 4c 89 4c 10 e8 mov %r9,-0x18(%rax,%rdx,1) 34: 4c 89 54 10 f0 mov %r10,-0x10(%rax,%rdx,1) 39: 4a 89 4c d8 20 mov %rcx,0x20(%rax,%r11,8) 3e: e9 .byte 0xe9 3f: 9b fwait --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.