Hello I found a bug in net/bpf in the lastest upstream linux and comfired in the lastest net tree and lastest net bpf titled BUG: unable to handle kernel paging request in bpf_probe_read_compat_str If you fix this issue, please add the following tag to the commit: Reported-by: xingwei Lee <xrivendell7@xxxxxxxxx> kernel: net 9702817384aa4a3700643d0b26e71deac0172cfd / bpf 2f2fee2bf74a7e31d06fc6cb7ba2bd4dd7753c99 Kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=b50bd31249191be8 in the lastest bpf tree, the crash like: TITLE: BUG: unable to handle kernel paging request in bpf_probe_read_compat_str CORRUPTED: false () MAINTAINERS (TO): [akpm@xxxxxxxxxxxxxxxxxxxx linux-mm@xxxxxxxxx] MAINTAINERS (CC): [linux-kernel@xxxxxxxxxxxxxxx] BUG: unable to handle page fault for address: ff0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD cf7a067 P4D cf7a067 PUD cf7c067 PMD cf9f067 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 8219 Comm: 9de Not tainted 6.7.0-rc41 Hardware name: QEMU Standard PC (i440FX + PIIX, 4 RIP: 0010:strncpy_from_kernel_nofault+0xc4/0x270 mm/maccess.c:91 Code: 83 85 6c 17 00 00 01 48 8b 2c 24 eb 18 e8 0 RSP: 0018:ffffc900114e7ac0 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffc900114e7b30 RCX:2 RDX: ffff8880183abcc0 RSI: ffffffff81b8c9c4 RDI:c RBP: ffffffffff600000 R08: 0000000000000001 R09:0 R10: 0000000000000001 R11: 0000000000000001 R12:8 R13: ffffffffff600000 R14: 0000000000000008 R15:0 FS: 0000000000000000(0000) GS:ffff88823bc00000(0 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600000 CR3: 000000000cf77000 CR4:0 PKRU: 55555554 Call Trace: <TASK> bpf_probe_read_kernel_str_common kernel/trace/bpf_trace.c:262 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline] bpf_probe_read_compat_str+0x12f/0x170 kernel/trace/bpf_trace.c:303 bpf_prog_f17ebaf3f5f7baf8+0x42/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1196 [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:2307 [inline] bpf_trace_run2+0x14e/0x410 kernel/trace/bpf_trace.c:2346 trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0xec/0x150 mm/slab_common.c:1043 vma_numab_state_free include/linux/mm.h:638 [inline] __vm_area_free+0x3e/0x140 kernel/fork.c:525 remove_vma+0x128/0x170 mm/mmap.c:146 exit_mmap+0x453/0xa70 mm/mmap.c:3332 __mmput+0x12a/0x4d0 kernel/fork.c:1349 mmput+0x62/0x70 kernel/fork.c:1371 exit_mm kernel/exit.c:567 [inline] do_exit+0x9aa/0x2ac0 kernel/exit.c:858 do_group_exit+0xd4/0x2a0 kernel/exit.c:1021 __do_sys_exit_group kernel/exit.c:1032 [inline] __se_sys_exit_group kernel/exit.c:1030 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1030 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x41/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b =* repro.c =* // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include <endian.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h> #ifndef __NR_bpf #define __NR_bpf 321 #endif #define BITMASK(bf_off, bf_len) (((1ull << (bf_len)) - 1) << (bf_off)) #define STORE_BY_BITMASK(type, htobe, addr, val, bf_off, bf_len) \ *(type*)(addr) = \ htobe((htobe(*(type*)(addr)) & ~BITMASK((bf_off), (bf_len))) | \ (((type)(val) << (bf_off)) & BITMASK((bf_off), (bf_len)))) uint64_t r[1] = {0xffffffffffffffff}; int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=*/7ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul); intptr_t res = 0; *(uint32_t*)0x200000c0 = 0x11; *(uint32_t*)0x200000c4 = 0xb; *(uint64_t*)0x200000c8 = 0x20000180; *(uint8_t*)0x20000180 = 0x18; STORE_BY_BITMASK(uint8_t, , 0x20000181, 0, 0, 4); STORE_BY_BITMASK(uint8_t, , 0x20000181, 0, 4, 4); *(uint16_t*)0x20000182 = 0; *(uint32_t*)0x20000184 = 0; *(uint8_t*)0x20000188 = 0; *(uint8_t*)0x20000189 = 0; *(uint16_t*)0x2000018a = 0; *(uint32_t*)0x2000018c = 0; *(uint8_t*)0x20000190 = 0x18; STORE_BY_BITMASK(uint8_t, , 0x20000191, 1, 0, 4); STORE_BY_BITMASK(uint8_t, , 0x20000191, 0, 4, 4); *(uint16_t*)0x20000192 = 0; *(uint32_t*)0x20000194 = 0x25702020; *(uint8_t*)0x20000198 = 0; *(uint8_t*)0x20000199 = 0; *(uint16_t*)0x2000019a = 0; *(uint32_t*)0x2000019c = 0x20202000; STORE_BY_BITMASK(uint8_t, , 0x200001a0, 3, 0, 3); STORE_BY_BITMASK(uint8_t, , 0x200001a0, 3, 3, 2); STORE_BY_BITMASK(uint8_t, , 0x200001a0, 3, 5, 3); STORE_BY_BITMASK(uint8_t, , 0x200001a1, 0xa, 0, 4); STORE_BY_BITMASK(uint8_t, , 0x200001a1, 1, 4, 4); *(uint16_t*)0x200001a2 = 0xfff8; *(uint32_t*)0x200001a4 = 0; STORE_BY_BITMASK(uint8_t, , 0x200001a8, 7, 0, 3); STORE_BY_BITMASK(uint8_t, , 0x200001a8, 1, 3, 1); STORE_BY_BITMASK(uint8_t, , 0x200001a8, 0xb, 4, 4); STORE_BY_BITMASK(uint8_t, , 0x200001a9, 1, 0, 4); STORE_BY_BITMASK(uint8_t, , 0x200001a9, 0xa, 4, 4); *(uint16_t*)0x200001aa = 0; *(uint32_t*)0x200001ac = 0; STORE_BY_BITMASK(uint8_t, , 0x200001b0, 7, 0, 3); STORE_BY_BITMASK(uint8_t, , 0x200001b0, 0, 3, 1); STORE_BY_BITMASK(uint8_t, , 0x200001b0, 0, 4, 4); STORE_BY_BITMASK(uint8_t, , 0x200001b1, 1, 0, 4); STORE_BY_BITMASK(uint8_t, , 0x200001b1, 0, 4, 4); *(uint16_t*)0x200001b2 = 0; *(uint32_t*)0x200001b4 = 0xfffffff8; STORE_BY_BITMASK(uint8_t, , 0x200001b8, 7, 0, 3); STORE_BY_BITMASK(uint8_t, , 0x200001b8, 0, 3, 1); STORE_BY_BITMASK(uint8_t, , 0x200001b8, 0xb, 4, 4); STORE_BY_BITMASK(uint8_t, , 0x200001b9, 2, 0, 4); STORE_BY_BITMASK(uint8_t, , 0x200001b9, 0, 4, 4); *(uint16_t*)0x200001ba = 0; *(uint32_t*)0x200001bc = 8; STORE_BY_BITMASK(uint8_t, , 0x200001c0, 7, 0, 3); STORE_BY_BITMASK(uint8_t, , 0x200001c0, 0, 3, 1); STORE_BY_BITMASK(uint8_t, , 0x200001c0, 0xb, 4, 4); STORE_BY_BITMASK(uint8_t, , 0x200001c1, 3, 0, 4); STORE_BY_BITMASK(uint8_t, , 0x200001c1, 0, 4, 4); *(uint16_t*)0x200001c2 = 0; *(uint32_t*)0x200001c4 = 0xff600000; *(uint8_t*)0x200001c8 = 0x85; *(uint8_t*)0x200001c9 = 0; *(uint16_t*)0x200001ca = 0; *(uint32_t*)0x200001cc = 0x2d; *(uint8_t*)0x200001d0 = 0x95; *(uint8_t*)0x200001d1 = 0; *(uint16_t*)0x200001d2 = 0; *(uint32_t*)0x200001d4 = 0; *(uint64_t*)0x200000d0 = 0x20000200; memcpy((void*)0x20000200, "GPL\000", 4); *(uint32_t*)0x200000d8 = 0; *(uint32_t*)0x200000dc = 0; *(uint64_t*)0x200000e0 = 0; *(uint32_t*)0x200000e8 = 0; *(uint32_t*)0x200000ec = 0; memset((void*)0x200000f0, 0, 16); *(uint32_t*)0x20000100 = 0; *(uint32_t*)0x20000104 = 0; *(uint32_t*)0x20000108 = 0; *(uint32_t*)0x2000010c = 0; *(uint64_t*)0x20000110 = 0; *(uint32_t*)0x20000118 = 0; *(uint32_t*)0x2000011c = 0; *(uint64_t*)0x20000120 = 0; *(uint32_t*)0x20000128 = 0; *(uint32_t*)0x2000012c = 0; *(uint32_t*)0x20000130 = 0; *(uint32_t*)0x20000134 = 0; *(uint64_t*)0x20000138 = 0; *(uint64_t*)0x20000140 = 0; *(uint32_t*)0x20000148 = 0; *(uint32_t*)0x2000014c = 0; res = syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x200000c0ul, /*size=*/0x90ul); if (res != -1) r[0] = res; *(uint64_t*)0x20000540 = 0x20000000; memcpy((void*)0x20000000, "kfree\000", 6); *(uint32_t*)0x20000548 = r[0]; syscall(__NR_bpf, /*cmd=*/0x11ul, /*arg=*/0x20000540ul, /*size=*/0x10ul); return 0; } =* repro.txt =* r0 = bpf$PROG_LOAD(0x5, &(0x7f00000000c0)={0x11, 0xb, &(0x7f0000000180)=@framed={{}, [@printk={@p, {}, {}, {}, {}, {0x7, 0x0, 0xb, 0x3, 0x0, 0x0, 0xff600000}, {0x85, 0x0, 0x0, 0x2d}}]}, &(0x7f0000000200)='GPL\x00', 0x0, 0x0, 0x0, 0x0, 0x0, '\x00', 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, 0x90) bpf$BPF_RAW_TRACEPOINT_OPEN(0x11, &(0x7f0000000540)={&(0x7f0000000000)='kfree\x00', r0}, 0x10) See aslo https://gist.github.com/xrivendell7/7bb1f0a30ccc2899fe7ea34bef882067 I hope it helps. Best regards. xingwei Lee
