Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1465347
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v4 32/57] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace() |
| Date | 2016-08-18 15:30 +0200 |
| Message-ID | <s7vyr-kW-83@gated-at.bofh.it> (permalink) |
| References | <s7vf3-dJ-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
show_stack_log_lvl() and dump_trace() are already preemption safe:
- If they're running in irq or exception context, preemption is already
disabled and the percpu stack pointers can be trusted.
- If they're running with preemption enabled, they must be running on
the task stack anyway, so it doesn't matter if they're comparing the
stack pointer against a percpu stack pointer from this CPU or another
one: either way it won't match.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
arch/x86/kernel/dumpstack_32.c | 14 ++++++--------
arch/x86/kernel/dumpstack_64.c | 26 +++++++++-----------------
2 files changed, 15 insertions(+), 25 deletions(-)
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index c533b8b..b07d5c9 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -24,16 +24,16 @@ static void *is_irq_stack(void *p, void *irq)
}
-static void *is_hardirq_stack(unsigned long *stack, int cpu)
+static void *is_hardirq_stack(unsigned long *stack)
{
- void *irq = per_cpu(hardirq_stack, cpu);
+ void *irq = this_cpu_read(hardirq_stack);
return is_irq_stack(stack, irq);
}
-static void *is_softirq_stack(unsigned long *stack, int cpu)
+static void *is_softirq_stack(unsigned long *stack);
{
- void *irq = per_cpu(softirq_stack, cpu);
+ void *irq = this_cpu_read(softirq_stack);
return is_irq_stack(stack, irq);
}
@@ -42,7 +42,6 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
- const unsigned cpu = get_cpu();
int graph = 0;
u32 *prev_esp;
@@ -53,9 +52,9 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
for (;;) {
void *end_stack;
- end_stack = is_hardirq_stack(stack, cpu);
+ end_stack = is_hardirq_stack(stack);
if (!end_stack)
- end_stack = is_softirq_stack(stack, cpu);
+ end_stack = is_softirq_stack(stack);
bp = ops->walk_stack(task, stack, bp, ops, data,
end_stack, &graph);
@@ -74,7 +73,6 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
break;
touch_nmi_watchdog();
}
- put_cpu();
}
EXPORT_SYMBOL(dump_trace);
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 491f2fd..f1b843a 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -31,8 +31,8 @@ static char x86_stack_ids[][8] = {
#endif
};
-static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
- unsigned *usedp, char **idp)
+static unsigned long *in_exception_stack(unsigned long stack, unsigned *usedp,
+ char **idp)
{
unsigned k;
@@ -41,7 +41,7 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
* 'stack' is in one of them:
*/
for (k = 0; k < N_EXCEPTION_STACKS; k++) {
- unsigned long end = per_cpu(orig_ist, cpu).ist[k];
+ unsigned long end = raw_cpu_ptr(&orig_ist)->ist[k];
/*
* Is 'stack' above this exception frame's end?
* If yes then skip to the next frame.
@@ -111,7 +111,7 @@ enum stack_type {
};
static enum stack_type
-analyze_stack(int cpu, struct task_struct *task, unsigned long *stack,
+analyze_stack(struct task_struct *task, unsigned long *stack,
unsigned long **stack_end, unsigned long *irq_stack,
unsigned *used, char **id)
{
@@ -121,8 +121,7 @@ analyze_stack(int cpu, struct task_struct *task, unsigned long *stack,
if ((unsigned long)task_stack_page(task) == addr)
return STACK_IS_NORMAL;
- *stack_end = in_exception_stack(cpu, (unsigned long)stack,
- used, id);
+ *stack_end = in_exception_stack((unsigned long)stack, used, id);
if (*stack_end)
return STACK_IS_EXCEPTION;
@@ -149,8 +148,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
- const unsigned cpu = get_cpu();
- unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
+ unsigned long *irq_stack = (unsigned long *)this_cpu_read(irq_stack_ptr);
unsigned used = 0;
int graph = 0;
int done = 0;
@@ -169,8 +167,8 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
enum stack_type stype;
char *id;
- stype = analyze_stack(cpu, task, stack, &stack_end,
- irq_stack, &used, &id);
+ stype = analyze_stack(task, stack, &stack_end, irq_stack, &used,
+ &id);
/* Default finish unless specified to continue */
done = 1;
@@ -225,7 +223,6 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
* This handles the process stack:
*/
bp = ops->walk_stack(task, stack, bp, ops, data, NULL, &graph);
- put_cpu();
}
EXPORT_SYMBOL(dump_trace);
@@ -236,13 +233,9 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *irq_stack_end;
unsigned long *irq_stack;
unsigned long *stack;
- int cpu;
int i;
- preempt_disable();
- cpu = smp_processor_id();
-
- irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
+ irq_stack_end = (unsigned long *)this_cpu_read(irq_stack_ptr);
irq_stack = irq_stack_end - (IRQ_USABLE_STACK_SIZE / sizeof(long));
sp = sp ? : get_stack_pointer(task, regs);
@@ -274,7 +267,6 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
stack++;
touch_nmi_watchdog();
}
- preempt_enable();
pr_cont("\n");
show_trace_log_lvl(task, regs, sp, bp, log_lvl);
--
2.7.4
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:20 +0200
[PATCH v4 52/57] x86/dumpstack: warn on stack recursion Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:20 +0200
[PATCH v4 46/57] x86/dumpstack: fix duplicate RIP address display in __show_regs() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:20 +0200
[PATCH v4 28/57] x86/dumpstack/ftrace: convert dump_trace() callbacks to use ftrace_graph_ret_addr() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 29/57] ftrace/x86: implement HAVE_FUNCTION_GRAPH_RET_ADDR_PTR Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 26/57] ftrace: add return address pointer to ftrace_ret_stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 34/57] x86/dumpstack: add get_stack_info() interface Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 23/57] proc: fix return address printk conversion specifer in /proc/<pid>/stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 36/57] x86/unwind: add new unwind interface and implementations Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 21/57] perf/x86: check perf_callchain_store() error Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 33/57] x86/dumpstack: simplify in_exception_stack() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 27/57] ftrace: add ftrace_graph_ret_addr() stack unwinding helpers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 19/57] x86/entry/head/32: use local labels Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 25/57] ftrace: only allocate the ret_stack 'fp' field when needed Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 16/57] x86/entry/32: fix the end of the stack for newly forked tasks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 40/57] x86/dumpstack: convert show_trace_log_lvl() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 39/57] oprofile/x86: convert x86_backtrace() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 35/57] x86/dumpstack: add recursion checking for all stacks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 22/57] oprofile/x86: add regs->ip to oprofile trace Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 38/57] x86/stacktrace: convert save_stack_trace_*() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 24/57] ftrace: remove CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST from config Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 45/57] x86/dumpstack: print any pt_regs found on the stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 30/57] x86/dumpstack/ftrace: mark function graph handler function as unreliable Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 47/57] x86/dumpstack: print orig_ax in __show_regs() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 44/57] x86/dumpstack: print stack identifier on its own line Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Frederic Weisbecker <fweisbec@gmail.com> - 2016-08-18 15:30 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Ingo Molnar <mingo@kernel.org> - 2016-08-18 15:40 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Steven Rostedt <rostedt@goodmis.org> - 2016-08-18 16:40 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 16:40 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Steven Rostedt <rostedt@goodmis.org> - 2016-08-18 16:50 +0200
Re: [PATCH v4 00/57] x86/dumpstack: rewrite x86 stack dump code Ingo Molnar <mingo@kernel.org> - 2016-08-19 07:10 +0200
[PATCH v4 41/57] x86/dumpstack: remove dump_trace() and related callbacks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 31/57] x86/dumpstack/ftrace: don't print unreliable addresses in print_context_stack_bp() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 42/57] x86/entry/unwind: create stack frames for saved interrupt registers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 20/57] x86/entry/32: rename 'error_code' to 'common_exception' Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 37/57] perf/x86: convert perf_callchain_kernel() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 32/57] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:30 +0200
[PATCH v4 12/57] x86: move _stext marker to before head code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:40 +0200
[PATCH v4 09/57] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-18 15:40 +0200
csiph-web