diff options
| author | Dmitry Safonov <dima@arista.com> | 2020-06-29 15:48:47 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-07-22 23:56:54 +0200 |
| commit | ef2ff0f5d6008d325c9a068e20981c0d0acc4d6b (patch) | |
| tree | 8d6761752741ea317dec5dda26efac8fba9bc2e3 | |
| parent | 44e215352cf17333992d56941b5bf4af60a67609 (diff) | |
x86/dumpstack: Show registers dump with trace's log levelx86-core-2020-08-03
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).
After all preparations are done, provide log_lvl parameter for
show_regs_if_on_stack() and wire up to actual log level used as
an argument for show_trace_log_lvl().
[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/20200629144847.492794-4-dima@arista.com
| -rw-r--r-- | arch/x86/kernel/dumpstack.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 4954d6678cef..f9a3526af15d 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -134,7 +134,7 @@ void show_iret_regs(struct pt_regs *regs, const char *log_lvl) } static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs, - bool partial) + bool partial, const char *log_lvl) { /* * These on_stack() checks aren't strictly necessary: the unwind code @@ -146,7 +146,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs, * they can be printed in the right context. */ if (!partial && on_stack(info, regs, sizeof(*regs))) { - __show_regs(regs, SHOW_REGS_SHORT, KERN_DEFAULT); + __show_regs(regs, SHOW_REGS_SHORT, log_lvl); } else if (partial && on_stack(info, (void *)regs + IRET_FRAME_OFFSET, IRET_FRAME_SIZE)) { @@ -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, KERN_DEFAULT); + show_iret_regs(regs, log_lvl); } } @@ -210,7 +210,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, printk("%s <%s>\n", log_lvl, stack_name); if (regs) - show_regs_if_on_stack(&stack_info, regs, partial); + show_regs_if_on_stack(&stack_info, regs, partial, log_lvl); /* * Scan the stack, printing any text addresses we find. At the @@ -271,7 +271,7 @@ next: /* if the frame has entry regs, print them */ regs = unwind_get_entry_regs(&state, &partial); if (regs) - show_regs_if_on_stack(&stack_info, regs, partial); + show_regs_if_on_stack(&stack_info, regs, partial, log_lvl); } if (stack_name) |