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Date: Wed, 3 Apr 2024 18:41:49 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: syzbot <syzbot+186522670e6722692d86@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
 syzkaller-bugs@googlegroups.com, bpf@vger.kernel.org
Subject: Re: [syzbot] [mm?] BUG: unable to handle kernel paging request in
 copy_from_kernel_nofault (2)
Message-Id: <20240403184149.0847a9d614f11b249529fd02@linux-foundation.org>
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On Mon, 01 Apr 2024 22:19:25 -0700 syzbot <syzbot+186522670e6722692d86@syzkaller.appspotmail.com> wrote:

> Hello,

Thanks.  Cc: bpf@vger.kernel.org

> syzbot found the following issue on:
> 
> HEAD commit:    317c7bc0ef03 Merge tag 'mmc-v6.9-rc1' of git://git.kernel...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1060bd41180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=43f1e0cbdb852271
> dashboard link: https://syzkaller.appspot.com/bug?extid=186522670e6722692d86
> compiler:       arm-linux-gnueabi-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: arm
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15751129180000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10136341180000
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/8ead8862021c/non_bootable_disk-317c7bc0.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/49458dc4ddf2/vmlinux-317c7bc0.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/031f516e5544/zImage-317c7bc0.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+186522670e6722692d86@syzkaller.appspotmail.com
> 
> 8<--- cut here ---
> Unable to handle kernel paging request at virtual address ffffffe9 when write
> [ffffffe9] *pgd=80000080007003, *pmd=deffd003, *pte=00000000
> Internal error: Oops: a07 [#1] PREEMPT SMP ARM
> Modules linked in:
> CPU: 1 PID: 3001 Comm: syz-executor291 Not tainted 6.9.0-rc1-syzkaller #0
> Hardware name: ARM-Versatile Express
> PC is at copy_from_kernel_nofault mm/maccess.c:38 [inline]
> PC is at copy_from_kernel_nofault+0xb8/0x12c mm/maccess.c:24
> LR is at copy_from_kernel_nofault+0x24/0x12c mm/maccess.c:31
> pc : [<804361f0>]    lr : [<8043615c>]    psr: a0000013
> sp : df96dc90  ip : df96dc90  fp : df96dcac
> r10: 00000000  r9 : df96dd40  r8 : ffffffe9
> r7 : 83d33c00  r6 : 00000005  r5 : ffffffe9  r4 : ffffffe9
> r3 : fffffff2  r2 : 00000000  r1 : 00000005  r0 : 00000001
> Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> Control: 30c5387d  Table: 8434d080  DAC: 00000000
> Register r0 information: non-paged memory
> Register r1 information: non-paged memory
> Register r2 information: NULL pointer
> Register r3 information: non-paged memory
> Register r4 information: non-paged memory
> Register r5 information: non-paged memory
> Register r6 information: non-paged memory
> Register r7 information: slab task_struct start 83d33c00 pointer offset 0 size 3072
> Register r8 information: non-paged memory
> Register r9 information: 2-page vmalloc region starting at 0xdf96c000 allocated at kernel_clone+0xac/0x3cc kernel/fork.c:2796
> Register r10 information: NULL pointer
> Register r11 information: 2-page vmalloc region starting at 0xdf96c000 allocated at kernel_clone+0xac/0x3cc kernel/fork.c:2796
> Register r12 information: 2-page vmalloc region starting at 0xdf96c000 allocated at kernel_clone+0xac/0x3cc kernel/fork.c:2796
> Process syz-executor291 (pid: 3001, stack limit = 0xdf96c000)
> Stack: (0xdf96dc90 to 0xdf96e000)
> dc80:                                     df96ddb8 ffffffe9 00000005 ffffffff
> dca0: df96dccc df96dcb0 8037c428 80436144 df96ddb8 00000000 8037c40c ffffffff
> dcc0: df96dd64 df96dcd0 7f011aa0 8037c418 ffffffe9 df96dd40 802ff648 81182b54
> dce0: df96dd64 df96dd30 35702575 00000000 828c0a94 40000013 00000000 00000000
> dd00: df96dcf0 00000000 df96dd74 df96dd18 df96dd2c df96dd20 81182b64 81898a78
> dd20: df96dd64 df96dd30 802ff648 81182b54 ffffffe9 df96dd40 00000005 00000000
> dd40: df96ddb8 00000000 df969000 842879c0 df969030 df96de30 df96ddfc df96dd68
> dd60: 8149c734 7f011a00 804d0184 8089c164 00000000 83d33c00 804b4cdc 804d0124
> dd80: 8260ca3c df96de30 00000001 df96de2c 80468494 00000000 df96ddb8 00000000
> dda0: 00000001 00000000 19df2b20 00000014 00000000 00000000 df969000 00000000
> ddc0: 00000000 00000000 84497800 f655f23e df96ddfc 842879c0 00000000 df96dec0
> dde0: 83f79c00 84497800 00000000 0000000e df96de64 df96de00 8149d6a0 8149c5d0
> de00: df96de30 00000000 00000000 df96de98 20000080 00000000 df969000 00000000
> de20: 828ffe80 82fe0000 8051cdd4 00000000 00000000 f655f23e 80395130 df969000
> de40: 00000028 df96de98 0000000a 20000080 00000028 00000000 df96df8c df96de68
> de60: 8039c858 8149d388 81c66394 84342c0c fcd9275f 00a00000 20000000 83d33c00
> de80: df96dee0 df96dfb0 df96dea4 df96de98 8089c348 df96dee0 20000080 00000000
> dea0: 83d33c00 df96ded0 00000008 00000000 00000008 80426e10 df96deec df96dec8
> dec0: 00000003 02000000 0000000e 00000055 20000140 00000000 20000380 00000000
> dee0: 00000000 04000000 00000000 00000000 00000000 00000000 00000000 00000000
> df00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> df20: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> df40: 00000000 00000000 00000000 00000000 00000000 00000000 20000000 f655f23e
> df60: 80216078 ffffffff 00000000 0008e050 00000182 80200288 83d33c00 00000182
> df80: df96dfa4 df96df90 8039dd98 8039b934 20000080 00000000 00000000 df96dfa8
> dfa0: 80200060 8039dd78 ffffffff 00000000 0000000a 20000080 00000028 00000000
> dfc0: ffffffff 00000000 0008e050 00000182 20000100 00000000 00000001 00003a97
> dfe0: 7ec66c70 7ec66c60 00010748 0002e890 00000010 0000000a 00000000 00000000
> Call trace: 
> [<80436138>] (copy_from_kernel_nofault) from [<8037c428>] (bpf_probe_read_kernel_common include/linux/bpf.h:2909 [inline])
> [<80436138>] (copy_from_kernel_nofault) from [<8037c428>] (____bpf_probe_read_kernel kernel/trace/bpf_trace.c:240 [inline])
> [<80436138>] (copy_from_kernel_nofault) from [<8037c428>] (bpf_probe_read_kernel+0x1c/0x44 kernel/trace/bpf_trace.c:237)
>  r7:ffffffff r6:00000005 r5:ffffffe9 r4:df96ddb8
> [<8037c40c>] (bpf_probe_read_kernel) from [<7f011aa0>] (bpf_prog_244768d4818575ac+0xac/0xc0)
>  r7:ffffffff r6:8037c40c r5:00000000 r4:df96ddb8
> [<7f0119f4>] (bpf_prog_244768d4818575ac) from [<8149c734>] (bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline])
> [<7f0119f4>] (bpf_prog_244768d4818575ac) from [<8149c734>] (__bpf_prog_run include/linux/filter.h:657 [inline])
> [<7f0119f4>] (bpf_prog_244768d4818575ac) from [<8149c734>] (bpf_prog_run include/linux/filter.h:664 [inline])
> [<7f0119f4>] (bpf_prog_244768d4818575ac) from [<8149c734>] (bpf_test_run+0x170/0x388 net/bpf/test_run.c:425)
>  r9:df96de30 r8:df969030 r7:842879c0 r6:df969000 r5:00000000 r4:df96ddb8
> [<8149c5c4>] (bpf_test_run) from [<8149d6a0>] (bpf_prog_test_run_skb+0x324/0x6cc net/bpf/test_run.c:1058)
>  r10:0000000e r9:00000000 r8:84497800 r7:83f79c00 r6:df96dec0 r5:00000000
>  r4:842879c0
> [<8149d37c>] (bpf_prog_test_run_skb) from [<8039c858>] (bpf_prog_test_run kernel/bpf/syscall.c:4240 [inline])
> [<8149d37c>] (bpf_prog_test_run_skb) from [<8039c858>] (__sys_bpf+0xf30/0x1ef0 kernel/bpf/syscall.c:5649)
>  r10:00000000 r9:00000028 r8:20000080 r7:0000000a r6:df96de98 r5:00000028
>  r4:df969000
> [<8039b928>] (__sys_bpf) from [<8039dd98>] (__do_sys_bpf kernel/bpf/syscall.c:5738 [inline])
> [<8039b928>] (__sys_bpf) from [<8039dd98>] (sys_bpf+0x2c/0x48 kernel/bpf/syscall.c:5736)
>  r10:00000182 r9:83d33c00 r8:80200288 r7:00000182 r6:0008e050 r5:00000000
>  r4:ffffffff
> [<8039dd6c>] (sys_bpf) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:66)
> Exception stack(0xdf96dfa8 to 0xdf96dff0)
> dfa0:                   ffffffff 00000000 0000000a 20000080 00000028 00000000
> dfc0: ffffffff 00000000 0008e050 00000182 20000100 00000000 00000001 00003a97
> dfe0: 7ec66c70 7ec66c60 00010748 0002e890
> Code: 9a000007 e3a03000 e4942000 e3530000 (e5852000) 
> ---[ end trace 0000000000000000 ]---
> ----------------
> Code disassembly (best guess):
>    0:	9a000007 	bls	0x24
>    4:	e3a03000 	mov	r3, #0
>    8:	e4942000 	ldr	r2, [r4], #0
>    c:	e3530000 	cmp	r3, #0
> * 10:	e5852000 	str	r2, [r5] <-- trapping instruction
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
> 
> syzbot will keep track of this issue. See:
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> 
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
> 
> If you want syzbot to run the reproducer, reply with:
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> If you attach or paste a git patch, syzbot will apply it before testing.
> 
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
> 
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
> 
> If you want to undo deduplication, reply with:
> #syz undup