syzbot


BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str

Status: fixed on 2024/04/08 12:30
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+a6a617741b9816d3f7c2@syzkaller.appspotmail.com
Fix commit: f175de546a3e x86/mm: Disallow vsyscall page read for copy_from_kernel_nofault()
First crash: 106d, last: 76d
Fix bisection: fixed by (bisect log) :
commit f175de546a3eb77614d94d4c02550181c0a8493e
Author: Hou Tao <houtao1@huawei.com>
Date: Fri Feb 2 10:39:34 2024 +0000

  x86/mm: Disallow vsyscall page read for copy_from_kernel_nofault()

  
Bug presence (2)
Date Name Commit Repro Result
2024/02/07 upstream (ToT) 99bd3cb0d12e C [report] BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str
2024/04/06 upstream (ToT) 6c6e47d69d82 C Failed due to an error; will retry later
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str mm C done 4 90d 106d 0/26 upstream: reported C repro on 2024/02/07 07:16
android-6-1 BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str origin:upstream missing-backport C 3 20d 110d 0/2 upstream: reported C repro on 2024/02/03 06:51
linux-5.15 BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str origin:upstream C done 1 76d 110d 3/3 fixed on 2024/04/08 12:30
android-5-15 BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str origin:upstream missing-backport C 2 15d 108d 0/2 upstream: reported C repro on 2024/02/05 22:23
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2024/04/08 07:56 4h30m bisect fix linux-6.1.y job log (1)
2024/03/08 04:39 1h11m bisect fix linux-6.1.y job log (0) log

Sample crash report:
BUG: unable to handle page fault for address: ffffffffff600000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD ce91067 P4D ce91067 PUD ce93067 PMD ceb6067 PTE 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 15 Comm: ksoftirqd/0 Not tainted 6.1.77-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:strncpy_from_kernel_nofault+0x89/0x1c0 mm/maccess.c:91
Code: 00 48 89 d0 48 c1 e8 03 48 89 44 24 10 0f b6 04 28 84 c0 48 89 14 24 0f 85 d5 00 00 00 ff 02 45 31 f6 49 89 df 48 8b 54 24 08 <42> 8a 1c 33 4a 8d 3c 32 48 89 f8 48 c1 e8 03 49 89 ec 0f b6 04 28
RSP: 0018:ffffc90000147868 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffff600000 RCX: ffff88813fef3b80
RDX: ffffc900001478e0 RSI: ffffffffff600000 RDI: ffffffffff600000
RBP: dffffc0000000000 R08: ffffffff813ddda9 R09: fffffbfff2092245
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffffff600000
R13: 0000000000000005 R14: 0000000000000000 R15: ffffffffff600000
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600000 CR3: 000000000ce8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bpf_probe_read_kernel_str_common kernel/trace/bpf_trace.c:265 [inline]
 ____bpf_probe_read_kernel_str kernel/trace/bpf_trace.c:274 [inline]
 bpf_probe_read_kernel_str+0x26/0x70 kernel/trace/bpf_trace.c:271
 bpf_prog_ef3a4661c9d1378e+0x42/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline]
 __bpf_prog_run include/linux/filter.h:600 [inline]
 bpf_prog_run include/linux/filter.h:607 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2275 [inline]
 bpf_trace_run2+0x1fd/0x410 kernel/trace/bpf_trace.c:2314
 __bpf_trace_kfree+0x6e/0x90 include/trace/events/kmem.h:94
 trace_kfree include/trace/events/kmem.h:94 [inline]
 kfree+0xf6/0x190 mm/slab_common.c:994
 security_task_free+0x96/0xc0 security/security.c:1704
 __put_task_struct+0xf4/0x280 kernel/fork.c:846
 rcu_do_batch kernel/rcu/tree.c:2296 [inline]
 rcu_core+0xad4/0x17e0 kernel/rcu/tree.c:2556
 __do_softirq+0x2e9/0xa4c kernel/softirq.c:571
 run_ksoftirqd+0xc1/0x120 kernel/softirq.c:934
 smpboot_thread_fn+0x52c/0xa30 kernel/smpboot.c:164
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
Modules linked in:
CR2: ffffffffff600000
---[ end trace 0000000000000000 ]---
RIP: 0010:strncpy_from_kernel_nofault+0x89/0x1c0 mm/maccess.c:91
Code: 00 48 89 d0 48 c1 e8 03 48 89 44 24 10 0f b6 04 28 84 c0 48 89 14 24 0f 85 d5 00 00 00 ff 02 45 31 f6 49 89 df 48 8b 54 24 08 <42> 8a 1c 33 4a 8d 3c 32 48 89 f8 48 c1 e8 03 49 89 ec 0f b6 04 28
RSP: 0018:ffffc90000147868 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffff600000 RCX: ffff88813fef3b80
RDX: ffffc900001478e0 RSI: ffffffffff600000 RDI: ffffffffff600000
RBP: dffffc0000000000 R08: ffffffff813ddda9 R09: fffffbfff2092245
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffffff600000
R13: 0000000000000005 R14: 0000000000000000 R15: ffffffffff600000
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600000 CR3: 000000000ce8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	00 48 89             	add    %cl,-0x77(%rax)
   3:	d0 48 c1             	rorb   -0x3f(%rax)
   6:	e8 03 48 89 44       	call   0x4489480e
   b:	24 10                	and    $0x10,%al
   d:	0f b6 04 28          	movzbl (%rax,%rbp,1),%eax
  11:	84 c0                	test   %al,%al
  13:	48 89 14 24          	mov    %rdx,(%rsp)
  17:	0f 85 d5 00 00 00    	jne    0xf2
  1d:	ff 02                	incl   (%rdx)
  1f:	45 31 f6             	xor    %r14d,%r14d
  22:	49 89 df             	mov    %rbx,%r15
  25:	48 8b 54 24 08       	mov    0x8(%rsp),%rdx
* 2a:	42 8a 1c 33          	mov    (%rbx,%r14,1),%bl <-- trapping instruction
  2e:	4a 8d 3c 32          	lea    (%rdx,%r14,1),%rdi
  32:	48 89 f8             	mov    %rdi,%rax
  35:	48 c1 e8 03          	shr    $0x3,%rax
  39:	49 89 ec             	mov    %rbp,%r12
  3c:	0f b6 04 28          	movzbl (%rax,%rbp,1),%eax

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/07 01:00 linux-6.1.y f1bb70486c9c 6404acf9 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str
* Struck through repros no longer work on HEAD.