* [PATCH] MIPS: Do not use smp_processor_id() in preemptible code
@ 2020-07-03 4:11 Xingxing Su
2020-07-05 9:48 ` Thomas Bogendoerfer
0 siblings, 1 reply; 2+ messages in thread
From: Xingxing Su @ 2020-07-03 4:11 UTC (permalink / raw)
To: Thomas Bogendoerfer, Huacai Chen, Jiaxun Yang
Cc: linux-mips, linux-kernel, Xuefeng Li, Tiezhu Yang
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] [<ffffffff80212ab4>] show_stack+0xa4/0x138
[ 22.025732] [<ffffffff8071cd60>] dump_stack+0xf0/0x150
[ 22.030903] [<ffffffff80c73f5c>] check_preemption_disabled+0xf4/0x100
[ 22.037375] [<ffffffff80213b84>] do_ri+0x1d4/0x690
[ 22.042198] [<ffffffff8020b828>] 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] [<ffffffff80212ab4>] show_stack+0xa4/0x138
[ 24.470029] [<ffffffff8071cd60>] dump_stack+0xf0/0x150
[ 24.475208] [<ffffffff80c73f5c>] check_preemption_disabled+0xf4/0x100
[ 24.481682] [<ffffffff80213b58>] do_ri+0x1a8/0x690
[ 24.486509] [<ffffffff8020b828>] handle_ri_int+0x44/0x5c
Signed-off-by: Xingxing Su <suxingxing@loongson.cn>
---
arch/mips/kernel/traps.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 7c32c95..a46ce94 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;
}
--
2.1.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] MIPS: Do not use smp_processor_id() in preemptible code
2020-07-03 4:11 [PATCH] MIPS: Do not use smp_processor_id() in preemptible code Xingxing Su
@ 2020-07-05 9:48 ` Thomas Bogendoerfer
0 siblings, 0 replies; 2+ messages in thread
From: Thomas Bogendoerfer @ 2020-07-05 9:48 UTC (permalink / raw)
To: Xingxing Su
Cc: Huacai Chen, Jiaxun Yang, linux-mips, linux-kernel, Xuefeng Li,
Tiezhu Yang
On Fri, Jul 03, 2020 at 12:11:58PM +0800, Xingxing Su wrote:
> 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] [<ffffffff80212ab4>] show_stack+0xa4/0x138
> [ 22.025732] [<ffffffff8071cd60>] dump_stack+0xf0/0x150
> [ 22.030903] [<ffffffff80c73f5c>] check_preemption_disabled+0xf4/0x100
> [ 22.037375] [<ffffffff80213b84>] do_ri+0x1d4/0x690
> [ 22.042198] [<ffffffff8020b828>] 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] [<ffffffff80212ab4>] show_stack+0xa4/0x138
> [ 24.470029] [<ffffffff8071cd60>] dump_stack+0xf0/0x150
> [ 24.475208] [<ffffffff80c73f5c>] check_preemption_disabled+0xf4/0x100
> [ 24.481682] [<ffffffff80213b58>] do_ri+0x1a8/0x690
> [ 24.486509] [<ffffffff8020b828>] handle_ri_int+0x44/0x5c
>
> Signed-off-by: Xingxing Su <suxingxing@loongson.cn>
> ---
> arch/mips/kernel/traps.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
applied to mips-fixes.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 2+ messages in thread
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