diff options
| author | Frank Ch. Eigler <fche@elastic.org> | 2008-04-13 17:50:45 -0400 |
|---|---|---|
| committer | Frank Ch. Eigler <fche@elastic.org> | 2008-04-13 17:50:45 -0400 |
| commit | f7e07777e033e580351dc6886ab7dbdddd9839fe (patch) | |
| tree | 07c4878e3eaf77801d5104c2f6c498cfff9e3bbd /runtime | |
| parent | a9f3ab125303a2e89dd3c17b39f26e1d2c428fa5 (diff) | |
| download | systemtap-steved-f7e07777e033e580351dc6886ab7dbdddd9839fe.tar.gz systemtap-steved-f7e07777e033e580351dc6886ab7dbdddd9839fe.tar.xz systemtap-steved-f7e07777e033e580351dc6886ab7dbdddd9839fe.zip | |
runtime backtrace: stop infinite loops by checking for full print buffer
2008-04-13 Frank Ch. Eigler <fche@elastic.org>
* print.c (_stp_pbuf_full): New function to note full print buffer.
* stack-{i386,x86_64}.c: Use it in all stack-searching loops, to
impose another limit against unbounded iteration.
Diffstat (limited to 'runtime')
| -rw-r--r-- | runtime/ChangeLog | 6 | ||||
| -rw-r--r-- | runtime/print.c | 10 | ||||
| -rw-r--r-- | runtime/stack-i386.c | 9 | ||||
| -rw-r--r-- | runtime/stack-x86_64.c | 3 |
4 files changed, 24 insertions, 4 deletions
diff --git a/runtime/ChangeLog b/runtime/ChangeLog index 067c5820..09a3e35d 100644 --- a/runtime/ChangeLog +++ b/runtime/ChangeLog @@ -1,3 +1,9 @@ +2008-04-13 Frank Ch. Eigler <fche@elastic.org> + + * print.c (_stp_pbuf_full): New function to note full print buffer. + * stack-{i386,x86_64}.c: Use it in all stack-searching loops, to + impose another limit against unbounded iteration. + 2008-03-31 Martin Hunt <hunt@redhat.com> * runtime.h (STP_USE_DWARF_UNWINDER): Define. diff --git a/runtime/print.c b/runtime/print.c index 0442ba09..4f99be7b 100644 --- a/runtime/print.c +++ b/runtime/print.c @@ -243,6 +243,16 @@ void _stp_print_char (const char c) pb->len ++; } +/** Check whether the print buffer is full. + * @return non-zero if full + */ + +static int _stp_pbuf_full (void) +{ + _stp_pbuf *pb = per_cpu_ptr(Stp_pbuf, smp_processor_id()); + return (pb->len >= STP_BUFFER_SIZE); +} + /* This function is used when printing maps or stats. */ /* Probably belongs elsewhere, but is here for now. */ diff --git a/runtime/stack-i386.c b/runtime/stack-i386.c index 20c8eda5..78f89b0d 100644 --- a/runtime/stack-i386.c +++ b/runtime/stack-i386.c @@ -17,7 +17,8 @@ static int _stp_valid_stack_ptr(unsigned long context, unsigned long p) static void _stp_stack_print_fallback(unsigned long context, unsigned long stack, int verbose) { unsigned long addr; - while (_stp_valid_stack_ptr(context, stack)) { + while (_stp_valid_stack_ptr(context, stack) && + !_stp_pbuf_full()) { if (unlikely(_stp_read_address(addr, (unsigned long *)stack, KERNEL_DS))) { /* cannot access stack. give up. */ return; @@ -42,7 +43,8 @@ static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels) unsigned long ebp = regs->ebp; #endif /* STAPCONF_X86_UNIREGS */ - while (_stp_valid_stack_ptr(context, (unsigned long)ebp)) { + while (_stp_valid_stack_ptr(context, (unsigned long)ebp) && + !_stp_pbuf_full()) { if (unlikely(_stp_read_address(addr, (unsigned long *)(ebp + 4), KERNEL_DS))) { /* cannot access stack. give up. */ return; @@ -59,7 +61,8 @@ static void __stp_stack_print (struct pt_regs *regs, int verbose, int levels) struct unwind_frame_info info; arch_unw_init_frame_info(&info, regs); - while (!arch_unw_user_mode(&info)) { + while (!arch_unw_user_mode(&info) && + !_stp_pbuf_full ()) { int ret = unwind(&info); dbug_unwind(1, "ret=%d PC=%lx SP=%lx\n", ret, UNW_PC(&info), UNW_SP(&info)); if (ret == 0) { diff --git a/runtime/stack-x86_64.c b/runtime/stack-x86_64.c index ae8e446d..9915c594 100644 --- a/runtime/stack-x86_64.c +++ b/runtime/stack-x86_64.c @@ -12,7 +12,8 @@ static void _stp_stack_print_fallback(unsigned long stack, int verbose) { unsigned long addr; - while (stack & (THREAD_SIZE - 1)) { + while (stack & (THREAD_SIZE - 1) && + !_stp_pbuf_full()) { if (unlikely(_stp_read_address(addr, (unsigned long *)stack, KERNEL_DS))) { /* cannot access stack. give up. */ return; |