| Message ID | 20191106030542.868541-27-dima@arista.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | Add log level to show_stack() | expand |
Dmitry Safonov <dima@arista.com> writes: > Currently, the log-level of show_stack() depends on a platform > realization. It creates situations where the headers are printed with > lower log level or higher than the stacktrace (depending on > a platform or user). Yes, I've had bug reports where the stacktrace is missing, which is annoying. Thanks for trying to fix the problem. > Furthermore, it forces the logic decision from user to an architecture > side. In result, some users as sysrq/kdb/etc are doing tricks with > temporary rising console_loglevel while printing their messages. > And in result it not only may print unwanted messages from other CPUs, > but also omit printing at all in the unlucky case where the printk() > was deferred. > > Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems > an easier approach than introducing more printk buffers. > Also, it will consolidate printings with headers. > > Introduce show_stack_loglvl(), that eventually will substitute > show_stack(). > > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Paul Mackerras <paulus@samba.org> > Cc: linuxppc-dev@lists.ozlabs.org > [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u > Signed-off-by: Dmitry Safonov <dima@arista.com> > --- > arch/powerpc/kernel/process.c | 18 +++++++++++++----- > 1 file changed, 13 insertions(+), 5 deletions(-) This looks good to me. Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) cheers > diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c > index 639ceae7da9d..34b46680a196 100644 > --- a/arch/powerpc/kernel/process.c > +++ b/arch/powerpc/kernel/process.c > @@ -2028,7 +2028,8 @@ unsigned long get_wchan(struct task_struct *p) > > static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; > > -void show_stack(struct task_struct *tsk, unsigned long *stack) > +void show_stack_loglvl(struct task_struct *tsk, unsigned long *stack, > + const char *loglvl) > { > unsigned long sp, ip, lr, newsp; > int count = 0; > @@ -2053,7 +2054,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) > } > > lr = 0; > - printk("Call Trace:\n"); > + printk("%sCall Trace:\n", loglvl); > do { > if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) > break; > @@ -2062,7 +2063,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) > newsp = stack[0]; > ip = stack[STACK_FRAME_LR_SAVE]; > if (!firstframe || ip != lr) { > - printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip); > + printk("%s["REG"] ["REG"] %pS", > + loglvl, sp, ip, (void *)ip); > #ifdef CONFIG_FUNCTION_GRAPH_TRACER > ret_addr = ftrace_graph_ret_addr(current, > &ftrace_idx, ip, stack); > @@ -2084,8 +2086,9 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) > struct pt_regs *regs = (struct pt_regs *) > (sp + STACK_FRAME_OVERHEAD); > lr = regs->link; > - printk("--- interrupt: %lx at %pS\n LR = %pS\n", > - regs->trap, (void *)regs->nip, (void *)lr); > + printk("%s--- interrupt: %lx at %pS\n LR = %pS\n", > + loglvl, regs->trap, > + (void *)regs->nip, (void *)lr); > firstframe = 1; > } > > @@ -2095,6 +2098,11 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) > put_task_stack(tsk); > } > > +void show_stack(struct task_struct *tsk, unsigned long *stack) > +{ > + show_stack_loglvl(tsk, stack, KERN_DEFAULT); > +} > + > #ifdef CONFIG_PPC64 > /* Called with hard IRQs off */ > void notrace __ppc64_runlatch_on(void) > -- > 2.23.0
On 11/6/19 9:52 AM, Michael Ellerman wrote: > Dmitry Safonov <dima@arista.com> writes: >> Currently, the log-level of show_stack() depends on a platform >> realization. It creates situations where the headers are printed with >> lower log level or higher than the stacktrace (depending on >> a platform or user). > > Yes, I've had bug reports where the stacktrace is missing, which is > annoying. Thanks for trying to fix the problem. > >> Furthermore, it forces the logic decision from user to an architecture >> side. In result, some users as sysrq/kdb/etc are doing tricks with >> temporary rising console_loglevel while printing their messages. >> And in result it not only may print unwanted messages from other CPUs, >> but also omit printing at all in the unlucky case where the printk() >> was deferred. >> >> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems >> an easier approach than introducing more printk buffers. >> Also, it will consolidate printings with headers. >> >> Introduce show_stack_loglvl(), that eventually will substitute >> show_stack(). >> >> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> >> Cc: Michael Ellerman <mpe@ellerman.id.au> >> Cc: Paul Mackerras <paulus@samba.org> >> Cc: linuxppc-dev@lists.ozlabs.org >> [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u >> Signed-off-by: Dmitry Safonov <dima@arista.com> >> --- >> arch/powerpc/kernel/process.c | 18 +++++++++++++----- >> 1 file changed, 13 insertions(+), 5 deletions(-) > > This looks good to me. > > Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Thanks for the review and time!
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 639ceae7da9d..34b46680a196 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2028,7 +2028,8 @@ unsigned long get_wchan(struct task_struct *p) static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; -void show_stack(struct task_struct *tsk, unsigned long *stack) +void show_stack_loglvl(struct task_struct *tsk, unsigned long *stack, + const char *loglvl) { unsigned long sp, ip, lr, newsp; int count = 0; @@ -2053,7 +2054,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) } lr = 0; - printk("Call Trace:\n"); + printk("%sCall Trace:\n", loglvl); do { if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) break; @@ -2062,7 +2063,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) newsp = stack[0]; ip = stack[STACK_FRAME_LR_SAVE]; if (!firstframe || ip != lr) { - printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip); + printk("%s["REG"] ["REG"] %pS", + loglvl, sp, ip, (void *)ip); #ifdef CONFIG_FUNCTION_GRAPH_TRACER ret_addr = ftrace_graph_ret_addr(current, &ftrace_idx, ip, stack); @@ -2084,8 +2086,9 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) struct pt_regs *regs = (struct pt_regs *) (sp + STACK_FRAME_OVERHEAD); lr = regs->link; - printk("--- interrupt: %lx at %pS\n LR = %pS\n", - regs->trap, (void *)regs->nip, (void *)lr); + printk("%s--- interrupt: %lx at %pS\n LR = %pS\n", + loglvl, regs->trap, + (void *)regs->nip, (void *)lr); firstframe = 1; } @@ -2095,6 +2098,11 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) put_task_stack(tsk); } +void show_stack(struct task_struct *tsk, unsigned long *stack) +{ + show_stack_loglvl(tsk, stack, KERN_DEFAULT); +} + #ifdef CONFIG_PPC64 /* Called with hard IRQs off */ void notrace __ppc64_runlatch_on(void)
Currently, the log-level of show_stack() depends on a platform realization. It creates situations where the headers are printed with lower log level or higher than the stacktrace (depending on a platform or user). Furthermore, it forces the logic decision from user to an architecture side. In result, some users as sysrq/kdb/etc are doing tricks with temporary rising console_loglevel while printing their messages. And in result it not only may print unwanted messages from other CPUs, but also omit printing at all in the unlucky case where the printk() was deferred. Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier approach than introducing more printk buffers. Also, it will consolidate printings with headers. Introduce show_stack_loglvl(), that eventually will substitute show_stack(). Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: linuxppc-dev@lists.ozlabs.org [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Signed-off-by: Dmitry Safonov <dima@arista.com> --- arch/powerpc/kernel/process.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)