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e9e14a558f8ab-3761d7707a1mr1485865ab.4.1718808604178; Wed, 19 Jun 2024 07:50:04 -0700 (PDT) Date: Wed, 19 Jun 2024 07:50:04 -0700 In-Reply-To: X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000004a1500061b3f500f@google.com> Subject: Re: [syzbot] [mm?] BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, wojciech.gladysz@infogain.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: BUG: unable to handle kernel paging request in bpf_probe_read_kernel_str BUG: unable to handle page fault for address: ffffffffff600000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD df36067 P4D df36067 PUD df38067 PMD df5b067 PTE 0 Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 PID: 4523 Comm: udevd Not tainted 6.8.0-rc1-syzkaller-00199-gee0e39a63b78 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 RIP: 0010:strncpy_from_kernel_nofault+0x8d/0x1d0 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 d9 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:ffffc9000318f828 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffffff600000 RCX: ffff88807b8f3b80 RDX: ffffc9000318f8a0 RSI: ffffffffff600000 RDI: ffffffffff600000 RBP: dffffc0000000000 R08: ffffffff8141da1d R09: 1ffffffff2590c84 R10: dffffc0000000000 R11: ffffffffa00016e8 R12: ffffffffff600000 R13: 0000000000000005 R14: 0000000000000000 R15: ffffffffff600000 FS: 00007f0b374b1c80(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600000 CR3: 000000002981c000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bpf_probe_read_kernel_str_common kernel/trace/bpf_trace.c:266 [inline] ____bpf_probe_read_kernel_str kernel/trace/bpf_trace.c:275 [inline] bpf_probe_read_kernel_str+0x2a/0x70 kernel/trace/bpf_trace.c:272 bpf_prog_ef3a4661c9d1378e+0x4a/0x4c bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline] __bpf_prog_run include/linux/filter.h:651 [inline] bpf_prog_run include/linux/filter.h:658 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] bpf_trace_run2+0x204/0x420 kernel/trace/bpf_trace.c:2420 trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x28e/0x380 mm/slub.c:4396 tomoyo_realpath_from_path+0xc2/0x5e0 security/tomoyo/realpath.c:250 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x2b7/0x740 security/tomoyo/file.c:822 tomoyo_path_unlink+0xd0/0x110 security/tomoyo/tomoyo.c:162 security_path_unlink+0xe1/0x140 security/security.c:1851 do_unlinkat+0x3e6/0x830 fs/namei.c:4395 __do_sys_unlink fs/namei.c:4446 [inline] __se_sys_unlink fs/namei.c:4444 [inline] __x64_sys_unlink+0x49/0x60 fs/namei.c:4444 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f0b37117da7 Code: f0 ff ff 73 01 c3 48 8b 0d 7e 90 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 90 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffeacb64188 EFLAGS: 00000202 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 00007f0b37117da7 RDX: fffffffffffffe60 RSI: 00007ffeacb64260 RDI: 000055bb027950d8 RBP: 000000000000000b R08: 0000000000000007 R09: 2905dc5b2145fa13 R10: c8f27f571a018b9b R11: 0000000000000202 R12: 0000000000000bb8 R13: 0000000200000001 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: CR2: ffffffffff600000 ---[ end trace 0000000000000000 ]--- RIP: 0010:strncpy_from_kernel_nofault+0x8d/0x1d0 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 d9 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:ffffc9000318f828 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffffff600000 RCX: ffff88807b8f3b80 RDX: ffffc9000318f8a0 RSI: ffffffffff600000 RDI: ffffffffff600000 RBP: dffffc0000000000 R08: ffffffff8141da1d R09: 1ffffffff2590c84 R10: dffffc0000000000 R11: ffffffffa00016e8 R12: ffffffffff600000 R13: 0000000000000005 R14: 0000000000000000 R15: ffffffffff600000 FS: 00007f0b374b1c80(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600000 CR3: 000000002981c000 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 d9 00 00 00 jne 0xf6 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 Tested on: commit: ee0e39a6 x86/mm: Move is_vsyscall_vaddr() into asm/vsy.. git tree: https://linux.googlesource.com/linux/kernel/git/torvalds/linux console output: https://syzkaller.appspot.com/x/log.txt?x=15ab2d41980000 kernel config: https://syzkaller.appspot.com/x/.config?x=5e23375d0c3afdc8 dashboard link: https://syzkaller.appspot.com/bug?extid=a0fa177e13690b663c74 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Note: no patches were applied.