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| author | Dmitry Safonov <dima@arista.com> | 2020-06-29 17:48:45 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-07-23 00:56:53 +0300 |
| commit | fd07f802a70935fbbfb9cc2d11e1d8ac95f28e44 (patch) | |
| tree | b80bc617474e8a625cc4bd461c6740a63ac67646 /arch/x86/kernel/dumpstack.c | |
| parent | ba47d845d715a010f7b51f6f89bae32845e6acb7 (diff) | |
| download | linux-fd07f802a70935fbbfb9cc2d11e1d8ac95f28e44.tar.xz | |
x86/dumpstack: Add log_lvl to show_iret_regs()
show_trace_log_lvl() provides x86 platform-specific way to unwind
backtrace with a given log level. Unfortunately, registers dump(s) are
not printed with the same log level - instead, KERN_DEFAULT is always
used.
Arista's switches uses quite common setup with rsyslog, where only
urgent messages goes to console (console_log_level=KERN_ERR), everything
else goes into /var/log/ as the console baud-rate often is indecently
slow (9600 bps).
Backtrace dumps without registers printed have proven to be as useful as
morning standups. Furthermore, in order to introduce KERN_UNSUPPRESSED
(which I believe is still the most elegant way to fix raciness of sysrq[1])
the log level should be passed down the stack to register dumping
functions. Besides, there is a potential use-case for printing traces
with KERN_DEBUG level [2] (where registers dump shouldn't appear with
higher log level).
Add log_lvl parameter to show_iret_regs() as a preparation to add it
to __show_regs() and show_regs_if_on_stack().
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/
[2]: https://lore.kernel.org/linux-doc/20190724170249.9644-1-dima@arista.com/
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Petr Mladek <pmladek@suse.com>
Link: https://lkml.kernel.org/r/20200629144847.492794-2-dima@arista.com
Diffstat (limited to 'arch/x86/kernel/dumpstack.c')
| -rw-r--r-- | arch/x86/kernel/dumpstack.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index b037cfa7c0c5..c36d629a25a8 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -126,10 +126,10 @@ void show_ip(struct pt_regs *regs, const char *loglvl) show_opcodes(regs, loglvl); } -void show_iret_regs(struct pt_regs *regs) +void show_iret_regs(struct pt_regs *regs, const char *log_lvl) { - show_ip(regs, KERN_DEFAULT); - printk(KERN_DEFAULT "RSP: %04x:%016lx EFLAGS: %08lx", (int)regs->ss, + show_ip(regs, log_lvl); + printk("%sRSP: %04x:%016lx EFLAGS: %08lx", log_lvl, (int)regs->ss, regs->sp, regs->flags); } @@ -155,7 +155,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs, * full pt_regs might not have been saved yet. In that case * just print the iret frame. */ - show_iret_regs(regs); + show_iret_regs(regs, KERN_DEFAULT); } } |