From: Xianting Tian xianting.tian@linux.alibaba.com
commit 357628e68f5c08ad578a718dc62a0031e06dbe91 upstream.
Use __smp_processor_id() to avoid check the preemption context when CONFIG_DEBUG_PREEMPT enabled, as we will enter crash kernel and no return.
Without the patch, [ 103.781044] sysrq: Trigger a crash [ 103.784625] Kernel panic - not syncing: sysrq triggered crash [ 103.837634] CPU1: off [ 103.889668] CPU2: off [ 103.933479] CPU3: off [ 103.939424] Starting crashdump kernel... [ 103.943442] BUG: using smp_processor_id() in preemptible [00000000] code: sh/346 [ 103.950884] caller is debug_smp_processor_id+0x1c/0x26 [ 103.956051] CPU: 0 PID: 346 Comm: sh Kdump: loaded Not tainted 5.10.113-00002-gce03f03bf4ec-dirty #149 [ 103.965355] Call Trace: [ 103.967805] [<ffffffe00020372a>] walk_stackframe+0x0/0xa2 [ 103.973206] [<ffffffe000bcf1f4>] show_stack+0x32/0x3e [ 103.978258] [<ffffffe000bd382a>] dump_stack_lvl+0x72/0x8e [ 103.983655] [<ffffffe000bd385a>] dump_stack+0x14/0x1c [ 103.988705] [<ffffffe000bdc8fe>] check_preemption_disabled+0x9e/0xaa [ 103.995057] [<ffffffe000bdc926>] debug_smp_processor_id+0x1c/0x26 [ 104.001150] [<ffffffe000206c64>] machine_kexec+0x22/0xd0 [ 104.006463] [<ffffffe000291a7e>] __crash_kexec+0x6a/0xa4 [ 104.011774] [<ffffffe000bcf3fa>] panic+0xfc/0x2b0 [ 104.016480] [<ffffffe000656ca4>] sysrq_reset_seq_param_set+0x0/0x70 [ 104.022745] [<ffffffe000657310>] __handle_sysrq+0x8c/0x154 [ 104.028229] [<ffffffe0006577e8>] write_sysrq_trigger+0x5a/0x6a [ 104.034061] [<ffffffe0003d90e0>] proc_reg_write+0x58/0xd4 [ 104.039459] [<ffffffe00036cff4>] vfs_write+0x7e/0x254 [ 104.044509] [<ffffffe00036d2f6>] ksys_write+0x58/0xbe [ 104.049558] [<ffffffe00036d36a>] sys_write+0xe/0x16 [ 104.054434] [<ffffffe000201b9a>] ret_from_syscall+0x0/0x2 [ 104.067863] Will call new kernel at ecc00000 from hart id 0 [ 104.074939] FDT image at fc5ee000 [ 104.079523] Bye...
With the patch we can got clear output, [ 67.740553] sysrq: Trigger a crash [ 67.744166] Kernel panic - not syncing: sysrq triggered crash [ 67.809123] CPU1: off [ 67.865210] CPU2: off [ 67.909075] CPU3: off [ 67.919123] Starting crashdump kernel... [ 67.924900] Will call new kernel at ecc00000 from hart id 0 [ 67.932045] FDT image at fc5ee000 [ 67.935560] Bye...
Fixes: 0e105f1d0037 ("riscv: use hart id instead of cpu id on machine_kexec") Reviewed-by: Guo Ren guoren@kernel.org Reviewed-by: Heiko Stuebner heiko@sntech.de Reviewed-by: Atish Patra atishp@rivosinc.com Signed-off-by: Xianting Tian xianting.tian@linux.alibaba.com Link: https://lore.kernel.org/r/20220811074150.3020189-2-xianting.tian@linux.aliba... Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/kernel/machine_kexec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/riscv/kernel/machine_kexec.c +++ b/arch/riscv/kernel/machine_kexec.c @@ -171,7 +171,7 @@ machine_kexec(struct kimage *image) struct kimage_arch *internal = &image->arch; unsigned long jump_addr = (unsigned long) image->start; unsigned long first_ind_entry = (unsigned long) &image->head; - unsigned long this_cpu_id = smp_processor_id(); + unsigned long this_cpu_id = __smp_processor_id(); unsigned long this_hart_id = cpuid_to_hartid_map(this_cpu_id); unsigned long fdt_addr = internal->fdt_addr; void *control_code_buffer = page_address(image->control_code_page);