From e8e999cf3cc733482e390b02ff25a64cecdc0b64 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 18 Mar 2011 11:40:06 +0900 Subject: x86, dumpstack: Correct stack dump info when frame pointer is available Current stack dump code scans entire stack and check each entry contains a pointer to kernel code. If CONFIG_FRAME_POINTER=y it could mark whether the pointer is valid or not based on value of the frame pointer. Invalid entries could be preceded by '?' sign. However this was not going to happen because scan start point was always higher than the frame pointer so that they could not meet. Commit 9c0729dc8062 ("x86: Eliminate bp argument from the stack tracing routines") delayed bp acquisition point, so the bp was read in lower frame, thus all of the entries were marked invalid. This patch fixes this by reverting above commit while retaining stack_frame() helper as suggested by Frederic Weisbecker. End result looks like below: before: [ 3.508329] Call Trace: [ 3.508551] [] ? panic+0x91/0x199 [ 3.508662] [] ? printk+0x68/0x6a [ 3.508770] [] ? mount_block_root+0x257/0x26e [ 3.508876] [] ? mount_root+0x56/0x5a [ 3.508975] [] ? prepare_namespace+0x170/0x1a9 [ 3.509216] [] ? kernel_init+0x1d2/0x1e2 [ 3.509335] [] ? kernel_thread_helper+0x4/0x10 [ 3.509442] [] ? restore_args+0x0/0x30 [ 3.509542] [] ? kernel_init+0x0/0x1e2 [ 3.509641] [] ? kernel_thread_helper+0x0/0x10 after: [ 3.522991] Call Trace: [ 3.523351] [] panic+0x91/0x199 [ 3.523468] [] ? printk+0x68/0x6a [ 3.523576] [] mount_block_root+0x257/0x26e [ 3.523681] [] mount_root+0x56/0x5a [ 3.523780] [] prepare_namespace+0x170/0x1a9 [ 3.523885] [] kernel_init+0x1d2/0x1e2 [ 3.523987] [] kernel_thread_helper+0x4/0x10 [ 3.524228] [] ? restore_args+0x0/0x30 [ 3.524345] [] ? kernel_init+0x0/0x1e2 [ 3.524445] [] ? kernel_thread_helper+0x0/0x10 -v5: * fix build breakage with oprofile -v4: * use 0 instead of regs->bp * separate out printk changes -v3: * apply comment from Frederic * add a couple of printk fixes Signed-off-by: Namhyung Kim Acked-by: Peter Zijlstra Acked-by: Frederic Weisbecker Cc: Soren Sandmann Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Robert Richter LKML-Reference: <1300416006-3163-1-git-send-email-namhyung@gmail.com> Signed-off-by: Ingo Molnar --- arch/x86/oprofile/backtrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/oprofile/backtrace.c') diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c index 72cbec1..2d49d4e 100644 --- a/arch/x86/oprofile/backtrace.c +++ b/arch/x86/oprofile/backtrace.c @@ -126,7 +126,7 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth) if (!user_mode_vm(regs)) { unsigned long stack = kernel_stack_pointer(regs); if (depth) - dump_trace(NULL, regs, (unsigned long *)stack, + dump_trace(NULL, regs, (unsigned long *)stack, 0, &backtrace_ops, &depth); return; } -- cgit v1.1