On Wed, Apr 3, 2024 at 6:56 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Mon, 01 Apr 2024 22:19:25 -0700 syzbot <syzbot+186522670e6722692d86@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > Hello, > > Thanks. Cc: bpf@xxxxxxxxxxxxxxx I suspect the issue is not on bpf side. Looks like the bug is somewhere in arm32 bits. copy_from_kernel_nofault() is called from lots of places. bpf is just one user that is easy for syzbot to fuzz. Interestingly arm defines copy_from_kernel_nofault_allowed() that should have filtered out user addresses. In this case ffffffe9 is probably a kernel address? But the kernel is doing a write? Which makes no sense, since copy_from_kernel_nofault is probe reading. arm folks, pls take a look. > > 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@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > 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@xxxxxxxxxxxxxxxx. > > > > syzbot will keep track of this issue. See: > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > > > 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: > > #syz test: git://repo/address.git branch-or-commit-hash > > 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 >
