Hi, This crash can be triggered by executing the C reproducer for multiple times, which just keep loading the following prog as raw tracepoint into kmem_cache_free(). The prog send SIGSEGV to current via bpf_send_signal_thread(), after load this, whoever tries to free mem would trigger this, kernel crashed when this happens to init. Seems we should filter init out in bpf_send_signal_common() by is_global_init(current), or maybe we should check this in the verifier? This can be reproduced on: HEAD commit: 59fe41b5255f selftests/bpf: Add verifier test exercising jit PROBE_MEM logic git tree: bpf-next console output: https://pastebin.com/raw/FMgyvEnH kernel config : https://pastebin.com/raw/XeF6jU43 C reproducer : https://pastebin.com/raw/Tag5N893 func#0 @0 0: R1=ctx(off=0,imm=0) R10=fp0 0: (18) r0 = 0x0 ; R0_w=0 2: (18) r6 = 0x0 ; R6_w=0 4: (18) r7 = 0x0 ; R7_w=0 6: (18) r8 = 0x0 ; R8_w=0 8: (18) r9 = 0x0 ; R9_w=0 10: (2d) if r0 > r0 goto pc+2 last_idx 10 first_idx 0 regs=1 stack=0 before 8: (18) r9 = 0x0 regs=1 stack=0 before 6: (18) r8 = 0x0 regs=1 stack=0 before 4: (18) r7 = 0x0 regs=1 stack=0 before 2: (18) r6 = 0x0 regs=1 stack=0 before 0: (18) r0 = 0x0 last_idx 10 first_idx 0 regs=1 stack=0 before 8: (18) r9 = 0x0 regs=1 stack=0 before 6: (18) r8 = 0x0 regs=1 stack=0 before 4: (18) r7 = 0x0 regs=1 stack=0 before 2: (18) r6 = 0x0 regs=1 stack=0 before 0: (18) r0 = 0x0 11: R0_w=0 11: (b7) r1 = 11 ; R1_w=11 12: (85) call bpf_send_signal_thread#117 ; R0=scalar() 13: (95) exit processed 9 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 1 Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b CPU: 3 PID: 1 Comm: systemd Not tainted 6.1.0-09652-g59fe41b5255f #148 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x100/0x178 lib/dump_stack.c:106 panic+0x2c4/0x60f kernel/panic.c:275 do_exit.cold+0x63/0xe4 kernel/exit.c:789 do_group_exit+0xd4/0x2a0 kernel/exit.c:950 get_signal+0x2460/0x2600 kernel/signal.c:2858 arch_do_signal_or_restart+0x78/0x5d0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x55e738964df0 Code: 00 31 f6 89 ef 4c 8d 05 be 1b 0d 00 48 8d 15 b0 85 0c 00 31 c0 e8 f0 c3 ff ff e9 1c ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 <41> 57 41 56 41 55 41 54 41 89 fc 55 53 48 81 ec 48 01 00 00 64 48 RSP: 002b:00007ffeb8e87bb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000f7 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f29dc8a6bc1 RDX: 00007ffeb8e87bc0 RSI: 00007ffeb8e87cf0 RDI: 000000000000000b RBP: 00007ffeb90b73c0 R08: 0000000000000000 R09: 0000000000000002 R10: 0000000000000004 R11: 0000000000000246 R12: 00007f29dc3f76c8 R13: 000000000000294d R14: 0000000000000000 R15: 00007ffeb9686870 </TASK> Kernel Offset: disabled Rebooting in 86400 seconds..
