Commit 8539c128 authored Jun 08, 2020 by Dmitry Safonov Committed by Linus Torvalds Jun 09, 2020

s390: add show_stack_loglvl()

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().

[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u



Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200418201944.482088-29-dima@arista.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 0b3d4365

arch/s390/kernel/dumpstack.c

+11 −5

Original line number	Diff line number	Diff line
		@@ -126,18 +126,24 @@ unknown:
		return -EINVAL;
		}

		void show_stack(struct task_struct task, unsigned long stack)
		void show_stack_loglvl(struct task_struct task, unsigned long stack,
		const char *loglvl)
		{
		struct unwind_state state;

		printk("Call Trace:\n");
		printk("%sCall Trace:\n", loglvl);
		unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
		printk(state.reliable ? " [<%016lx>] %pSR \n" :
		"([<%016lx>] %pSR)\n",
		state.ip, (void *) state.ip);
		printk(state.reliable ? "%s [<%016lx>] %pSR \n" :
		"%s([<%016lx>] %pSR)\n",
		loglvl, state.ip, (void *) state.ip);
		debug_show_held_locks(task ? : current);
		}

		void show_stack(struct task_struct task, unsigned long stack)
		{
		show_stack_loglvl(task, stack, KERN_DEFAULT);
		}

		static void show_last_breaking_event(struct pt_regs *regs)
		{
		printk("Last Breaking-Event-Address:\n");

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