printk,kdb: capture printk() when in kdb shell
in [Kernel]
|
Prev: [PATCH 2/7] drm: add KGDB/KDB support Add support for KDB entry/exit.
Next: [PATCH 6/9] x86: initialize stack canary in secondary start
From: Andrew Morton on 12 Feb 2010 18:00 On Fri, 12 Feb 2010 16:35:37 -0600 Jason Wessel <jason.wessel(a)windriver.com> wrote: > @@ -609,6 +610,14 @@ asmlinkage int printk(const char *fmt, ...) > va_list args; > int r; > > +#ifdef CONFIG_KGDB_KDB > + if (unlikely(kdb_trap_printk)) { > + va_start(args, fmt); > + r = vkdb_printf(fmt, args); > + va_end(args); > + return r; > + } > +#endif > va_start(args, fmt); > r = vprintk(fmt, args); > va_end(args); this? --- a/kernel/printk.c~a +++ a/kernel/printk.c @@ -594,7 +594,11 @@ asmlinkage int printk(const char *fmt, . int r; va_start(args, fmt); +#ifdef CONFIG_KGDB_KDB + r = vkdb_printf(fmt, args); +#else r = vprintk(fmt, args); +#endif va_end(args); return r; _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Jason Wessel on 12 Feb 2010 18:30 Andrew Morton wrote: > On Fri, 12 Feb 2010 16:35:37 -0600 Jason Wessel <jason.wessel(a)windriver.com> wrote: > > >> @@ -609,6 +610,14 @@ asmlinkage int printk(const char *fmt, ...) >> va_list args; >> int r; >> >> +#ifdef CONFIG_KGDB_KDB >> + if (unlikely(kdb_trap_printk)) { >> + va_start(args, fmt); >> + r = vkdb_printf(fmt, args); >> + va_end(args); >> + return r; >> + } >> +#endif >> va_start(args, fmt); >> r = vprintk(fmt, args); >> va_end(args); >> > > this? > > --- a/kernel/printk.c~a > +++ a/kernel/printk.c > @@ -594,7 +594,11 @@ asmlinkage int printk(const char *fmt, . > int r; > > va_start(args, fmt); > +#ifdef CONFIG_KGDB_KDB > + r = vkdb_printf(fmt, args); > +#else > r = vprintk(fmt, args); > +#endif > va_end(args); > > return r; > _ > If you feel that would be cleaner, I can make that change, but I would also have to call vprintk() from vkdb_printf when ever kdb_trap_printk is not set. Do I understand your recommendation correctly? The only time the kdb_trap_printk is ever set comes when we are inside the kernel debug shell, and do something like "bt". It serves the purpose of letting folks run the stack dumper and a few other functions. We want to trap printk's in this instance because we don't want them in the log them and also for the case when your debug connection is not actually a system log console, or if you run the command via gdb (example is "monitor bt"). Thanks, Jason. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andrew Morton on 12 Feb 2010 23:50 On Fri, 12 Feb 2010 17:20:22 -0600 Jason Wessel <jason.wessel(a)windriver.com> wrote: > Andrew Morton wrote: > > On Fri, 12 Feb 2010 16:35:37 -0600 Jason Wessel <jason.wessel(a)windriver.com> wrote: > > > > > >> @@ -609,6 +610,14 @@ asmlinkage int printk(const char *fmt, ...) > >> va_list args; > >> int r; > >> > >> +#ifdef CONFIG_KGDB_KDB > >> + if (unlikely(kdb_trap_printk)) { > >> + va_start(args, fmt); > >> + r = vkdb_printf(fmt, args); > >> + va_end(args); > >> + return r; > >> + } > >> +#endif > >> va_start(args, fmt); > >> r = vprintk(fmt, args); > >> va_end(args); > >> > > > > this? > > > > --- a/kernel/printk.c~a > > +++ a/kernel/printk.c > > @@ -594,7 +594,11 @@ asmlinkage int printk(const char *fmt, . > > int r; > > > > va_start(args, fmt); > > +#ifdef CONFIG_KGDB_KDB > > + r = vkdb_printf(fmt, args); > > +#else > > r = vprintk(fmt, args); > > +#endif > > va_end(args); > > > > return r; > > _ > > > > If you feel that would be cleaner, I can make that change, but I would > also have to call vprintk() from vkdb_printf when ever kdb_trap_printk > is not set. Do I understand your recommendation correctly? > err, no, I must have been in a drunken stupor. Was trying to find a way to avoid the code duplication. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Jason Wessel on 15 Feb 2010 22:20
Andrew Morton wrote: > On Fri, 12 Feb 2010 17:20:22 -0600 Jason Wessel <jason.wessel(a)windriver.com> wrote: > > >> If you feel that would be cleaner, I can make that change, but I would >> also have to call vprintk() from vkdb_printf when ever kdb_trap_printk >> is not set. Do I understand your recommendation correctly? >> >> > > Was trying to find > a way to avoid the code duplication. > > > You did make me think about the interface a bit further. If you were going to ack one of the versions of this patch, which would you prefer? The previous version, this new version or something else? The difference here is that we use a replaced function call vs using the if statement. There are more lines source in the kdb, but the interface api is clean. Thanks, Jason. |