diff options
| -rw-r--r-- | arch/tile/kernel/stack.c | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c index ea2e0ce28380..0d54106be3d6 100644 --- a/arch/tile/kernel/stack.c +++ b/arch/tile/kernel/stack.c @@ -30,6 +30,10 @@ #include <arch/abi.h> #include <arch/interrupts.h> +#define KBT_ONGOING 0 /* Backtrace still ongoing */ +#define KBT_DONE 1 /* Backtrace cleanly completed */ +#define KBT_RUNNING 2 /* Can't run backtrace on a running task */ +#define KBT_LOOP 3 /* Backtrace entered a loop */ /* Is address on the specified kernel stack? */ static int in_kernel_stack(struct KBacktraceIterator *kbt, VirtualAddress sp) @@ -207,11 +211,11 @@ static int KBacktraceIterator_next_item_inclusive( for (;;) { do { if (!KBacktraceIterator_is_sigreturn(kbt)) - return 1; + return KBT_ONGOING; } while (backtrace_next(&kbt->it)); if (!KBacktraceIterator_restart(kbt)) - return 0; + return KBT_DONE; } } @@ -264,7 +268,7 @@ void KBacktraceIterator_init(struct KBacktraceIterator *kbt, kbt->pgtable = NULL; kbt->verbose = 0; /* override in caller if desired */ kbt->profile = 0; /* override in caller if desired */ - kbt->end = 0; + kbt->end = KBT_ONGOING; kbt->new_context = 0; if (is_current) { HV_PhysAddr pgdir_pa = hv_inquire_context().page_table; @@ -290,7 +294,7 @@ void KBacktraceIterator_init(struct KBacktraceIterator *kbt, if (regs == NULL) { if (is_current || t->state == TASK_RUNNING) { /* Can't do this; we need registers */ - kbt->end = 1; + kbt->end = KBT_RUNNING; return; } pc = get_switch_to_pc(); @@ -305,26 +309,29 @@ void KBacktraceIterator_init(struct KBacktraceIterator *kbt, } backtrace_init(&kbt->it, read_memory_func, kbt, pc, lr, sp, r52); - kbt->end = !KBacktraceIterator_next_item_inclusive(kbt); + kbt->end = KBacktraceIterator_next_item_inclusive(kbt); } EXPORT_SYMBOL(KBacktraceIterator_init); int KBacktraceIterator_end(struct KBacktraceIterator *kbt) { - return kbt->end; + return kbt->end != KBT_ONGOING; } EXPORT_SYMBOL(KBacktraceIterator_end); void KBacktraceIterator_next(struct KBacktraceIterator *kbt) { + VirtualAddress old_pc = kbt->it.pc, old_sp = kbt->it.sp; kbt->new_context = 0; - if (!backtrace_next(&kbt->it) && - !KBacktraceIterator_restart(kbt)) { - kbt->end = 1; - return; - } - - kbt->end = !KBacktraceIterator_next_item_inclusive(kbt); + if (!backtrace_next(&kbt->it) && !KBacktraceIterator_restart(kbt)) { + kbt->end = KBT_DONE; + return; + } + kbt->end = KBacktraceIterator_next_item_inclusive(kbt); + if (old_pc == kbt->it.pc && old_sp == kbt->it.sp) { + /* Trapped in a loop; give up. */ + kbt->end = KBT_LOOP; + } } EXPORT_SYMBOL(KBacktraceIterator_next); @@ -387,6 +394,8 @@ void tile_show_stack(struct KBacktraceIterator *kbt, int headers) break; } } + if (kbt->end == KBT_LOOP) + pr_err("Stack dump stopped; next frame identical to this one\n"); if (headers) pr_err("Stack dump complete\n"); } |