From 5868347a192afb99b189d72946ab6a321b6115ac Mon Sep 17 00:00:00 2001 From: Xingxing Su Date: Fri, 3 Jul 2020 12:11:58 +0800 Subject: MIPS: Do not use smp_processor_id() in preemptible code Use preempt_disable() to fix the following bug under CONFIG_DEBUG_PREEMPT. [ 21.915305] BUG: using smp_processor_id() in preemptible [00000000] code: qemu-system-mip/1056 [ 21.923996] caller is do_ri+0x1d4/0x690 [ 21.927921] CPU: 0 PID: 1056 Comm: qemu-system-mip Not tainted 5.8.0-rc2 #3 [ 21.934913] Stack : 0000000000000001 ffffffff81370000 ffffffff8071cd60 a80f926d5ac95694 [ 21.942984] a80f926d5ac95694 0000000000000000 98000007f0043c88 ffffffff80f2fe40 [ 21.951054] 0000000000000000 0000000000000000 0000000000000001 0000000000000000 [ 21.959123] ffffffff802d60cc 98000007f0043dd8 ffffffff81f4b1e8 ffffffff81f60000 [ 21.967192] ffffffff81f60000 ffffffff80fe0000 ffff000000000000 0000000000000000 [ 21.975261] fffffffff500cce1 0000000000000001 0000000000000002 0000000000000000 [ 21.983331] ffffffff80fe1a40 0000000000000006 ffffffff8077f940 0000000000000000 [ 21.991401] ffffffff81460000 98000007f0040000 98000007f0043c80 000000fffba8cf20 [ 21.999471] ffffffff8071cd60 0000000000000000 0000000000000000 0000000000000000 [ 22.007541] 0000000000000000 0000000000000000 ffffffff80212ab4 a80f926d5ac95694 [ 22.015610] ... [ 22.018086] Call Trace: [ 22.020562] [] show_stack+0xa4/0x138 [ 22.025732] [] dump_stack+0xf0/0x150 [ 22.030903] [] check_preemption_disabled+0xf4/0x100 [ 22.037375] [] do_ri+0x1d4/0x690 [ 22.042198] [] handle_ri_int+0x44/0x5c [ 24.359386] BUG: using smp_processor_id() in preemptible [00000000] code: qemu-system-mip/1072 [ 24.368204] caller is do_ri+0x1a8/0x690 [ 24.372169] CPU: 4 PID: 1072 Comm: qemu-system-mip Not tainted 5.8.0-rc2 #3 [ 24.379170] Stack : 0000000000000001 ffffffff81370000 ffffffff8071cd60 a80f926d5ac95694 [ 24.387246] a80f926d5ac95694 0000000000000000 98001007ef06bc88 ffffffff80f2fe40 [ 24.395318] 0000000000000000 0000000000000000 0000000000000001 0000000000000000 [ 24.403389] ffffffff802d60cc 98001007ef06bdd8 ffffffff81f4b818 ffffffff81f60000 [ 24.411461] ffffffff81f60000 ffffffff80fe0000 ffff000000000000 0000000000000000 [ 24.419533] fffffffff500cce1 0000000000000001 0000000000000002 0000000000000000 [ 24.427603] ffffffff80fe0000 0000000000000006 ffffffff8077f940 0000000000000020 [ 24.435673] ffffffff81460020 98001007ef068000 98001007ef06bc80 000000fffbbbb370 [ 24.443745] ffffffff8071cd60 0000000000000000 0000000000000000 0000000000000000 [ 24.451816] 0000000000000000 0000000000000000 ffffffff80212ab4 a80f926d5ac95694 [ 24.459887] ... [ 24.462367] Call Trace: [ 24.464846] [] show_stack+0xa4/0x138 [ 24.470029] [] dump_stack+0xf0/0x150 [ 24.475208] [] check_preemption_disabled+0xf4/0x100 [ 24.481682] [] do_ri+0x1a8/0x690 [ 24.486509] [] handle_ri_int+0x44/0x5c Signed-off-by: Xingxing Su Signed-off-by: Thomas Bogendoerfer --- arch/mips/kernel/traps.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'arch/mips/kernel') diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 1234ea21dd8f..f655af68176c 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -723,12 +723,14 @@ static int simulate_loongson3_cpucfg(struct pt_regs *regs, perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0); /* Do not emulate on unsupported core models. */ - if (!loongson3_cpucfg_emulation_enabled(¤t_cpu_data)) + preempt_disable(); + if (!loongson3_cpucfg_emulation_enabled(¤t_cpu_data)) { + preempt_enable(); return -1; - + } regs->regs[rd] = loongson3_cpucfg_read_synthesized( ¤t_cpu_data, sel); - + preempt_enable(); return 0; } -- cgit v1.2.3-58-ga151