• Jason Wessel's avatar
    panic: fix stack dump print on direct call to panic() · 026ee1f6
    Jason Wessel authored
    Commit 6e6f0a1f ("panic: don't print redundant backtraces on oops")
    causes a regression where no stack trace will be printed at all for the
    case where kernel code calls panic() directly while not processing an
    oops, and of course there are 100's of instances of this type of call.
    
    The original commit executed the check (!oops_in_progress), but this will
    always be false because just before the dump_stack() there is a call to
    bust_spinlocks(1), which does the following:
    
      void __attribute__((weak)) bust_spinlocks(int yes)
      {
    	if (yes) {
    		++oops_in_progress;
    
    The proper way to resolve the problem that original commit tried to
    solve is to avoid printing a stack dump from panic() when the either of
    the following conditions is true:
    
      1) TAINT_DIE has been set (this is done by oops_end())
         This indicates and oops has already been printed.
      2) oops_in_progress > 1
         This guards against the rare case where panic() is invoked
         a second time, or in between oops_begin() and oops_end()
    Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
    Cc: Andi Kleen <ak@linux.intel.com>
    Cc: <stable@vger.kernel.org>	[3.3+]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    026ee1f6
panic.c 10.9 KB