[Crash-utility] Re: [PATCH] arm64: fix a potential segfault in arm64_unwind_frame

Date: Thu, 18 Jul 2024 07:26:02 -0000 From:qiwu.chen@transsion.com Subject: [Crash-utility] Re: [PATCH] arm64: fix a potential segfault in arm64_unwind_frame To:devel@lists.crash-utility.osci.io Message-ID:<20240718072602.21739.62283@lists.crash-utility.osci.io> Content-Type: text/plain; charset="utf-8" Hi Lianbo, 1. The current issue can be reproduced with arm64_unwind_frame_v2():

crash> bt [Detaching after fork from child process 4778] Thread 1 "crash" received signal SIGSEGV, Segmentation fault. 0x0000555555826dae in arm64_unwind_frame_v2 (bt=0x7fffffffd8f0, frame=0x7fffffffd060, ofp=0x555559909970) at arm64.c:3048 3048 frame->pc = GET_STACK_ULONG(fp + 8); (gdb) bt #0 0x0000555555826dae in arm64_unwind_frame_v2 (bt=0x7fffffffd8f0, frame=0x7fffffffd060, ofp=0x555559909970) at arm64.c:3048 #1 0x0000555555827d99 in arm64_back_trace_cmd_v2 (bt=0x7fffffffd8f0) at arm64.c:3426 #2 0x00005555557df95e in back_trace (bt=0x7fffffffd8f0) at kernel.c:3240 #3 0x00005555557dd8b8 in cmd_bt () at kernel.c:2881 #4 0x000055555573696b in exec_command () at main.c:893 #5 0x000055555573673e in main_loop () at main.c:840 #6 0x0000555555aa4a61 in captured_main (data=<optimized out>) at main.c:1284 #7 gdb_main (args=<optimized out>) at main.c:1313 #8 0x0000555555aa4ae0 in gdb_main_entry (argc=<optimized out>, argv=<optimized out>) at main.c:1338 #9 0x00005555558021df in gdb_main_loop (argc=2, argv=0x7fffffffe248) at gdb_interface.c:81 #10 0x0000555555736401 in main (argc=3, argv=0x7fffffffe248) at main.c:721 (gdb) p/x *(struct arm64_stackframe *)0x7fffffffd060 $1 = {fp = 0xffffffc008003f50, sp = 0xffffffc008003f40, pc = 0xffffffdfd669447c} (gdb) p/x *(struct bt_info *)0x7fffffffd8f0 $2 = {task = 0xffffff8118012500, flags = 0x0, instptr = 0xffffffdfd669447c, stkptr = 0xffffffc008003f40, bptr = 0x0, stackbase = 0xffffffc01b5b0000, stacktop = 0xffffffc01b5b4000, stackbuf = 0x555556117a80, tc = 0x55557a3b3480, hp = 0x0, textlist = 0x0, ref = 0x0, frameptr = 0xffffffc008003f50, call_target = 0x0, machdep = 0x0, debug = 0x0, eframe_ip = 0x0, radix = 0x0, cpumask = 0x0} 2. The issue can be easily reproduced by "echo c > /proc/sysrq-trigger" on Andriod GKI-5.10 platform. >From the reproduced dump we can see, the current fp/sp of crashing cpu1 is out of range task's stack, but located in the irq stack of cpu0 KERNEL: vmlinux [TAINTED] DUMPFILE: SYS_COREDUMP CPUS: 8 [OFFLINE: 7] MACHINE: aarch64 (unknown Mhz) MEMORY: 8 GB PANIC: "Kernel panic - not syncing: sysrq triggered crash" PID: 9089 COMMAND: "sh" TASK: ffffff8118012500 [THREAD_INFO: ffffff8118012500] CPU: 1 STATE: TASK_RUNNING (PANIC) crash> help -m |grep irq irq_stack_size: 16384 irq_stacks[0]: ffffffc008000000 irq_stacks[1]: ffffffc008008000 irq_stacks[2]: ffffffc008010000 irq_stacks[3]: ffffffc008018000 irq_stacks[4]: ffffffc008020000 irq_stacks[5]: ffffffc008028000 irq_stacks[6]: ffffffc008030000 irq_stacks[7]: ffffffc008038000 crash> task_struct.thread -x ffffff8118012500 thread = { cpu_context = { x19 = 0xffffff80c01ea500, x20 = 0xffffff8118012500, x21 = 0xffffff8118012500, x22 = 0xffffff80c01ea500, x23 = 0xffffff8118012500, x24 = 0xffffff81319ac270, x25 = 0xffffffdfd8f87000, x26 = 0xffffff8118012500, x27 = 0xffffffdfd88ea180, x28 = 0xffffffdfd7e1b4b8, fp = 0xffffffc01b5b3a10, sp = 0xffffffc01b5b3a10, pc = 0xffffffdfd667b89c }, crash> bt -S 0xffffffc01b5b3a10 PID: 9089 TASK: ffffff8118012500 CPU: 1 COMMAND: "sh" #0 [ffffffc008003f50] local_cpu_stop at ffffffdfd6694478 crash> bt -S ffffffc008003f50 PID: 9089 TASK: ffffff8118012500 CPU: 1 COMMAND: "sh" bt: non-process stack address for this task: ffffffc008003f50 (valid range: ffffffc01b5b0000 - ffffffc01b5b4000) The second frame begins to switch to irq stack of cpu0. crash> rd ffffffc008003f50 2 ffffffc008003f50: ffffffc008003f70 ffffffdfd68125d0 p?.......%...... crash> dis -x ffffffdfd68125d0 0xffffffdfd68125d0 <handle_percpu_devid_fasteoi_ipi+0xb0>: b 0xffffffdfd6812730 <handle_percpu_devid_fasteoi_ipi+0x210> crash> rd ffffffc008003f70 2 ffffffc008003f70: ffffffc008003fb0 ffffffdfd680352c .?......,5...... crash> dis ffffffdfd680352c -x 0xffffffdfd680352c <__handle_domain_irq+0x114>: bl 0xffffffdfd673d204 <__irq_exit_rcu> crash> rd ffffffc008003fb0 2 ffffffc008003fb0: ffffffc008003fe0 ffffffdfd6610380 .?........a..... crash> dis -x ffffffdfd6610380 0xffffffdfd6610380 <gic_handle_irq.30555+0x6c>: cbz w0, 0xffffffdfd6610348 <gic_handle_irq.30555+0x34> crash> rd ffffffc008003fe0 2 ffffffc008003fe0: ffffffdfd8d83e20 ffffffdfd6612624 >......$&a..... crash> dis -x ffffffdfd6612624 0xffffffdfd6612624 <el1_irq+0xe4>: mov sp, x19 crash> rd ffffffdfd8d83e20 2 ffffffdfd8d83e20: ffffffdfd8d83e80 ffffffdfd768c690 .>........h..... crash> dis -x ffffffdfd768c690 0xffffffdfd768c690 <cpuidle_enter_state+0x3a4>: tbnz w19, #31, 0xffffffdfd768c720 <cpuidle_enter_state+0x434> crash> rd ffffffdfd8d83e80 2 ffffffdfd8d83e80: ffffffdfd8d83ef0 ffffffdfd67ab4f4 .>........z..... crash> dis -x ffffffdfd67ab4f4 0xffffffdfd67ab4f4 <do_idle+0x308>: str xzr, [x19, #8] crash> rd ffffffdfd8d83ef0 2 ffffffdfd8d83ef0: ffffffdfd8d83f50 ffffffdfd67ab7e4 P?........z..... crash> dis -x ffffffdfd67ab7e4 0xffffffdfd67ab7e4 <cpu_startup_entry+0x84>: b 0xffffffdfd67ab7e0 <cpu_startup_entry+0x80> It's unreasonable cpu1 is in cpu0's irq context, which is far away from the backtrace showed by "bt -T", so we must avoid this case. crash> bt -T PID: 9089 TASK: ffffff8118012500 CPU: 1 COMMAND: "sh" [ffffffc01b5b3238] vsnprintf at ffffffdfd7075c10 [ffffffc01b5b32b8] sprintf at ffffffdfd707b9e4 [ffffffc01b5b3398] __sprint_symbol at ffffffdfd68abff4 [ffffffc01b5b33c8] symbol_string at ffffffdfd70774ac [ffffffc01b5b33d8] symbol_string at ffffffdfd7077510 [ffffffc01b5b34c8] string at ffffffdfd70767a8 [ffffffc01b5b34d8] vsnprintf at ffffffdfd7075c2c [ffffffc01b5b34e8] vsnprintf at ffffffdfd7075fdc [ffffffc01b5b3518] vscnprintf at ffffffdfd707b8b4 [ffffffc01b5b3558] ktime_get_ts64 at ffffffdfd686a2f8 [ffffffc01b5b3598] data_alloc at ffffffdfd68009b4 [ffffffc01b5b35d8] prb_reserve at ffffffdfd68011b4 [ffffffc01b5b35e8] prb_reserve at ffffffdfd68010a0 [ffffffc01b5b3648] log_store at ffffffdfd67fb024 [ffffffc01b5b3698] number at ffffffdfd7076ea4 [ffffffc01b5b36d8] number at ffffffdfd7076ea4 [ffffffc01b5b3738] vsnprintf at ffffffdfd7075c10 [ffffffc01b5b3778] number at ffffffdfd7076ea4 [ffffffc01b5b37c8] number at ffffffdfd7076ea4 [ffffffc01b5b3828] vsnprintf at ffffffdfd7075c10 [ffffffc01b5b3868] vsnprintf at ffffffdfd7075c2c [ffffffc01b5b3888] number at ffffffdfd7076ea4 [ffffffc01b5b38e8] vsnprintf at ffffffdfd7075c10 [ffffffc01b5b3928] vsnprintf at ffffffdfd7075c2c [ffffffc01b5b3968] aee_nested_printf at ffffffdfd3d05d7c [mrdump] [ffffffc01b5b3a48] mrdump_common_die at ffffffdfd3d05a98 [mrdump] [ffffffc01b5b3ac8] ipanic at ffffffdfd3d06078 [mrdump] [ffffffc01b5b3ae8] __typeid__ZTSFiP14notifier_blockmPvE_global_addr at ffffffdfd7e3c118 [ffffffc01b5b3af0] ipanic.cfi_jt at ffffffdfd3d0ab40 [mrdump] [ffffffc01b5b3b18] atomic_notifier_call_chain at ffffffdfd678236c [ffffffc01b5b3b28] panic at ffffffdfd672aa28 [ffffffc01b5b3bf8] rcu_read_unlock.34874 at ffffffdfd718ddfc [ffffffc01b5b3c58] __handle_sysrq at ffffffdfd718d3c0 [ffffffc01b5b3c68] write_sysrq_trigger at ffffffdfd718ea20 [ffffffc01b5b3cb0] __typeid__ZTSFlP4filePKcmPxE_global_addr at ffffffdfd7e2fa88 [ffffffc01b5b3cc8] proc_reg_write at ffffffdfd6c56f44 [ffffffc01b5b3cd8] file_start_write at ffffffdfd6b3f884 [ffffffc01b5b3d08] vfs_write at ffffffdfd6b403b4 [ffffffc01b5b3da8] ksys_write at ffffffdfd6b40240 [ffffffc01b5b3df8] __arm64_sys_write at ffffffdfd6b401b4 [ffffffc01b5b3e20] __typeid__ZTSFlPK7pt_regsE_global_addr at ffffffdfd7e25240 [ffffffc01b5b3e38] el0_svc_common at ffffffdfd6695980 [ffffffc01b5b3e48] el0_da at ffffffdfd7d43e30 [ffffffc01b5b3e58] el0_svc at ffffffdfd7d43d9c [ffffffc01b5b3e98] el0_sync_handler at ffffffdfd7d43d10 [ffffffc01b5b3ea8] el0_sync at ffffffdfd66128b8 Thanks