linux-brain/kernel/stacktrace.c
Omar Sandoval 6b4af0dab8 stacktrace, lockdep: Fix address, newline ugliness
commit bfeda41d06 upstream.

Since KERN_CONT became meaningful again, lockdep stack traces have had
annoying extra newlines, like this:

[    5.561122] -> #1 (B){+.+...}:
[    5.561528]
[    5.561532] [<ffffffff810d8873>] lock_acquire+0xc3/0x210
[    5.562178]
[    5.562181] [<ffffffff816f6414>] mutex_lock_nested+0x74/0x6d0
[    5.562861]
[    5.562880] [<ffffffffa01aa3c3>] init_btrfs_fs+0x21/0x196 [btrfs]
[    5.563717]
[    5.563721] [<ffffffff81000472>] do_one_initcall+0x52/0x1b0
[    5.564554]
[    5.564559] [<ffffffff811a3af6>] do_init_module+0x5f/0x209
[    5.565357]
[    5.565361] [<ffffffff81122f4d>] load_module+0x218d/0x2b80
[    5.566020]
[    5.566021] [<ffffffff81123beb>] SyS_finit_module+0xeb/0x120
[    5.566694]
[    5.566696] [<ffffffff816fd241>] entry_SYSCALL_64_fastpath+0x1f/0xc2

That's happening because each printk() call now gets printed on its own
line, and we do a separate call to print the spaces before the symbol.
Fix it by doing the printk() directly instead of using the
print_ip_sym() helper.

Additionally, the symbol address isn't very helpful, so let's get rid of
that, too. The final result looks like this:

[    5.194518] -> #1 (B){+.+...}:
[    5.195002]        lock_acquire+0xc3/0x210
[    5.195439]        mutex_lock_nested+0x74/0x6d0
[    5.196491]        do_one_initcall+0x52/0x1b0
[    5.196939]        do_init_module+0x5f/0x209
[    5.197355]        load_module+0x218d/0x2b80
[    5.197792]        SyS_finit_module+0xeb/0x120
[    5.198251]        entry_SYSCALL_64_fastpath+0x1f/0xc2

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@fb.com
Fixes: 4bcc595ccd ("printk: reinstate KERN_CONT for printing continuation lines")
Link: http://lkml.kernel.org/r/43b4e114724b2bdb0308fa86cb33aa07d3d67fad.1486510315.git.osandov@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14 15:25:42 -08:00

72 lines
1.6 KiB
C

/*
* kernel/stacktrace.c
*
* Stack trace management functions
*
* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>
void print_stack_trace(struct stack_trace *trace, int spaces)
{
int i;
if (WARN_ON(!trace->entries))
return;
for (i = 0; i < trace->nr_entries; i++)
printk("%*c%pS\n", 1 + spaces, ' ', (void *)trace->entries[i]);
}
EXPORT_SYMBOL_GPL(print_stack_trace);
int snprint_stack_trace(char *buf, size_t size,
struct stack_trace *trace, int spaces)
{
int i;
int generated;
int total = 0;
if (WARN_ON(!trace->entries))
return 0;
for (i = 0; i < trace->nr_entries; i++) {
generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
(void *)trace->entries[i]);
total += generated;
/* Assume that generated isn't a negative number */
if (generated >= size) {
buf += size;
size = 0;
} else {
buf += generated;
size -= generated;
}
}
return total;
}
EXPORT_SYMBOL_GPL(snprint_stack_trace);
/*
* Architectures that do not implement save_stack_trace_tsk or
* save_stack_trace_regs get this weak alias and a once-per-bootup warning
* (whenever this facility is utilized - for example by procfs):
*/
__weak void
save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
}
__weak void
save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
}