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authorIngo Molnar <mingo@elte.hu>2006-06-23 02:04:20 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-23 07:42:56 -0700
commitb88d4f1d390a6a232938d27d551f24cf08a2c7e0 (patch)
treeeb0cf7af51b7049befc632a835722d5ee7660687
parentba528f2854e8632c8d04ddcd45f06c47bc7188b0 (diff)
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[PATCH] i386: break out of recursion in stackframe walk
If CONFIG_FRAME_POINTERS is enabled, and one does a dump_stack() during early SMP init, an infinite stackdump and a bootup hang happens: [<c0104e7f>] show_trace+0xd/0xf [<c0104e96>] dump_stack+0x15/0x17 [<c01440df>] save_trace+0xc3/0xce [<c014527d>] mark_lock+0x8c/0x4fe [<c0145df5>] __lockdep_acquire+0x44e/0xaa5 [<c0146798>] lockdep_acquire+0x68/0x84 [<c1048699>] _spin_lock+0x21/0x2f [<c010d918>] prepare_set+0xd/0x5d [<c010daa8>] generic_set_all+0x1d/0x201 [<c010ca9a>] mtrr_ap_init+0x23/0x3b [<c010ada8>] identify_cpu+0x2a7/0x2af [<c01192a7>] smp_store_cpu_info+0x2f/0xb4 [<c01197d0>] start_secondary+0xb5/0x3ec [<c104ec11>] end_of_stack_stop_unwind_function+0x1/0x4 [<c104ec11>] end_of_stack_stop_unwind_function+0x1/0x4 [<c104ec11>] end_of_stack_stop_unwind_function+0x1/0x4 [<c104ec11>] end_of_stack_stop_unwind_function+0x1/0x4 [<c104ec11>] end_of_stack_stop_unwind_function+0x1/0x4 [<c104ec11>] end_of_stack_stop_unwind_function+0x1/0x4 [<c104ec11>] end_of_stack_stop_unwind_function+0x1/0x4 [<c104ec11>] end_of_stack_stop_unwind_function+0x1/0x4 [...] Due to "end_of_stack_stop_unwind_function" recursing back to itself in the EBP stackframe-walker. So avoid this type of recursion when walking the stack . Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/i386/kernel/traps.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 0e49836..df9d210 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -149,6 +149,12 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo,
while (valid_stack_ptr(tinfo, (void *)ebp)) {
addr = *(unsigned long *)(ebp + 4);
printed = print_addr_and_symbol(addr, log_lvl, printed);
+ /*
+ * break out of recursive entries (such as
+ * end_of_stack_stop_unwind_function):
+ */
+ if (ebp == *(unsigned long *)ebp)
+ break;
ebp = *(unsigned long *)ebp;
}
#else