| Message ID | 1621076521-22412-3-git-send-email-yangtiezhu@loongson.cn (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | Update defconfig and fix kernel hang | expand |
On Sat, May 15, 2021 at 07:02:01PM +0800, Tiezhu Yang wrote: > When update the latest mainline kernel with the following three configs, > the kernel hangs during startup: > > (1) CONFIG_FUNCTION_GRAPH_TRACER=y > (2) CONFIG_PREEMPT_TRACER=y > (3) CONFIG_FTRACE_STARTUP_TEST=y > > When update the latest mainline kernel with the above two configs (1) > and (2), the kernel starts normally, but it still hangs when execute > the following command: > > echo "function_graph" > /sys/kernel/debug/tracing/current_tracer > > Without CONFIG_PREEMPT_TRACER=y, the above two kinds of kernel hangs > disappeared, so it seems that CONFIG_PREEMPT_TRACER has some influences > with function_graph tracer at the first glance. > > I use ejtag to find out the epc address is related with preempt_enable() > in the file arch/mips/lib/mips-atomic.c, because function tracing can > trace the preempt_{enable,disable} calls that are traced, replace them > with preempt_{enable,disable}_notrace to prevent function tracing from > going into an infinite loop, and then it can fix the kernel hang issue. > > By the way, it seems that this commit is a complement and improvement of > commit f93a1a00f2bd ("MIPS: Fix crash that occurs when function tracing > is enabled"). > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > Cc: Steven Rostedt <rostedt@goodmis.org> > --- > arch/mips/lib/mips-atomic.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) applied to mips-fixes. Thomas.
diff --git a/arch/mips/lib/mips-atomic.c b/arch/mips/lib/mips-atomic.c index de03838..a9b72ea 100644 --- a/arch/mips/lib/mips-atomic.c +++ b/arch/mips/lib/mips-atomic.c @@ -37,7 +37,7 @@ */ notrace void arch_local_irq_disable(void) { - preempt_disable(); + preempt_disable_notrace(); __asm__ __volatile__( " .set push \n" @@ -53,7 +53,7 @@ notrace void arch_local_irq_disable(void) : /* no inputs */ : "memory"); - preempt_enable(); + preempt_enable_notrace(); } EXPORT_SYMBOL(arch_local_irq_disable); @@ -61,7 +61,7 @@ notrace unsigned long arch_local_irq_save(void) { unsigned long flags; - preempt_disable(); + preempt_disable_notrace(); __asm__ __volatile__( " .set push \n" @@ -78,7 +78,7 @@ notrace unsigned long arch_local_irq_save(void) : /* no inputs */ : "memory"); - preempt_enable(); + preempt_enable_notrace(); return flags; } @@ -88,7 +88,7 @@ notrace void arch_local_irq_restore(unsigned long flags) { unsigned long __tmp1; - preempt_disable(); + preempt_disable_notrace(); __asm__ __volatile__( " .set push \n" @@ -106,7 +106,7 @@ notrace void arch_local_irq_restore(unsigned long flags) : "0" (flags) : "memory"); - preempt_enable(); + preempt_enable_notrace(); } EXPORT_SYMBOL(arch_local_irq_restore);
When update the latest mainline kernel with the following three configs, the kernel hangs during startup: (1) CONFIG_FUNCTION_GRAPH_TRACER=y (2) CONFIG_PREEMPT_TRACER=y (3) CONFIG_FTRACE_STARTUP_TEST=y When update the latest mainline kernel with the above two configs (1) and (2), the kernel starts normally, but it still hangs when execute the following command: echo "function_graph" > /sys/kernel/debug/tracing/current_tracer Without CONFIG_PREEMPT_TRACER=y, the above two kinds of kernel hangs disappeared, so it seems that CONFIG_PREEMPT_TRACER has some influences with function_graph tracer at the first glance. I use ejtag to find out the epc address is related with preempt_enable() in the file arch/mips/lib/mips-atomic.c, because function tracing can trace the preempt_{enable,disable} calls that are traced, replace them with preempt_{enable,disable}_notrace to prevent function tracing from going into an infinite loop, and then it can fix the kernel hang issue. By the way, it seems that this commit is a complement and improvement of commit f93a1a00f2bd ("MIPS: Fix crash that occurs when function tracing is enabled"). Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Steven Rostedt <rostedt@goodmis.org> --- arch/mips/lib/mips-atomic.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)