From: Omar Sandoval <[email protected]>
Since KERN_CONT became meaningful again, lockdep stack traces have
looked 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.
This is what it should look like:
[ 6.650322] -> #1 (B){+.+...}:
[ 6.651053] [<ffffffff810d8873>] lock_acquire+0xc3/0x210
[ 6.652000] [<ffffffff816f6414>] mutex_lock_nested+0x74/0x6d0
[ 6.652664] [<ffffffffa01b43c3>] init_btrfs_fs+0x21/0x196 [btrfs]
[ 6.653288] [<ffffffff81000472>] do_one_initcall+0x52/0x1b0
[ 6.653858] [<ffffffff811a3ae6>] do_init_module+0x5f/0x209
[ 6.654426] [<ffffffff81122f3d>] load_module+0x218d/0x2b80
[ 6.654992] [<ffffffff81123bdb>] SyS_finit_module+0xeb/0x120
[ 6.655591] [<ffffffff816fd241>] entry_SYSCALL_64_fastpath+0x1f/0xc2
Fix it by doing the printk() directly instead of using the
print_ip_sym() helper.
Fixes: 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation
lines")
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Linus Torvalds <[email protected]>
Signed-off-by: Omar Sandoval <[email protected]>
---
Patch is based on v4.10-rc7. That print_ip_sym() helper isn't all that
complicated and it probably causes more problems than it solves with
KERN_CONT and all. I'm not entirely sure who should take this, but it's
somewhat lockdep related, so it can probably go through tip for 4.11?
kernel/stacktrace.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index b6e4c16377c7..625573af2a3c 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -14,13 +14,14 @@
void print_stack_trace(struct stack_trace *trace, int spaces)
{
int i;
+ void *ip;
if (WARN_ON(!trace->entries))
return;
for (i = 0; i < trace->nr_entries; i++) {
- printk("%*c", 1 + spaces, ' ');
- print_ip_sym(trace->entries[i]);
+ ip = (void *)trace->entries[i];
+ printk("%*c[<%p>] %pS\n", 1 + spaces, ' ', ip, ip);
}
}
EXPORT_SYMBOL_GPL(print_stack_trace);
--
2.11.1
