Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1461243
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 31/51] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace() |
| Date | 2016-08-12 16:40 +0200 |
| Message-ID | <s5lMU-2Ra-93@gated-at.bofh.it> (permalink) |
| References | <s5lMR-2Ra-3@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 interrupt context, preemption is already
disabled and the percpu irq 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 the percpu irq 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 v3 00/51] x86/dumpstack: rewrite x86 stack dump code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 49/51] x86/dumpstack: warn on stack recursion Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 36/51] perf/x86: convert perf_callchain_kernel() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 26/51] ftrace: add ftrace_graph_ret_addr() stack unwinding helpers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 33/51] x86/dumpstack: add get_stack_info() interface Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 48/51] x86/unwind: warn if stack grows up Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 48/51] x86/unwind: warn if stack grows up Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:30 +0200
Re: [PATCH v3 48/51] x86/unwind: warn if stack grows up Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 18:30 +0200
[PATCH v3 50/51] x86/mm: move arch_within_stack_frames() to usercopy.c Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 50/51] x86/mm: move arch_within_stack_frames() to usercopy.c Kees Cook <keescook@chromium.org> - 2016-08-12 19:40 +0200
Re: [PATCH v3 50/51] x86/mm: move arch_within_stack_frames() to usercopy.c Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 21:20 +0200
Re: [PATCH v3 50/51] x86/mm: move arch_within_stack_frames() to usercopy.c Kees Cook <keescook@chromium.org> - 2016-08-12 22:10 +0200
Re: [PATCH v3 50/51] x86/mm: move arch_within_stack_frames() to usercopy.c Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 22:40 +0200
Re: [PATCH v3 50/51] x86/mm: move arch_within_stack_frames() to usercopy.c Kees Cook <keescook@chromium.org> - 2016-08-12 22:50 +0200
[PATCH v3 44/51] x86/dumpstack: print any pt_regs found on the stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 44/51] x86/dumpstack: print any pt_regs found on the stack Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:50 +0200
[PATCH v3 12/51] x86: move _stext marker to before head code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 32/51] x86/dumpstack: simplify in_exception_stack() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 32/51] x86/dumpstack: simplify in_exception_stack() Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:50 +0200
Re: [PATCH v3 32/51] x86/dumpstack: simplify in_exception_stack() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 17:40 +0200
[PATCH v3 14/51] x86/asm/head: put real return address on idle task stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 14/51] x86/asm/head: put real return address on idle task stack Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:40 +0200
Re: [PATCH v3 14/51] x86/asm/head: put real return address on idle task stack Nilay Vaish <nilayvaish@gmail.com> - 2016-08-17 22:40 +0200
Re: [PATCH v3 14/51] x86/asm/head: put real return address on idle task stack Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-17 23:20 +0200
[PATCH v3 16/51] x86/32: put real return address on stack in entry code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 16/51] x86/32: put real return address on stack in entry code Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:30 +0200
Re: [PATCH v3 16/51] x86/32: put real return address on stack in entry code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 17:10 +0200
Re: [PATCH v3 16/51] x86/32: put real return address on stack in entry code "H. Peter Anvin" <hpa@zytor.com> - 2016-08-15 20:10 +0200
Re: [PATCH v3 16/51] x86/32: put real return address on stack in entry code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 20:30 +0200
Re: [PATCH v3 16/51] x86/32: put real return address on stack in entry code "H. Peter Anvin" <hpa@zytor.com> - 2016-08-15 21:30 +0200
Re: [PATCH v3 16/51] x86/32: put real return address on stack in entry code Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 22:10 +0200
[PATCH v3 18/51] x86/entry/head/32: use local labels Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 30/51] x86/dumpstack/ftrace: don't print unreliable addresses in print_context_stack_bp() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 42/51] x86/unwind: create stack frames for saved syscall registers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 42/51] x86/unwind: create stack frames for saved syscall registers Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:40 +0200
Re: [PATCH v3 42/51] x86/unwind: create stack frames for saved syscall registers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 19:00 +0200
[PATCH v3 28/51] ftrace/x86: implement HAVE_FUNCTION_GRAPH_RET_ADDR_PTR Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 31/51] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 31/51] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace() Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:50 +0200
Re: [PATCH v3 31/51] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 17:40 +0200
[PATCH v3 41/51] x86/entry/unwind: create stack frames for saved interrupt registers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
Re: [PATCH v3 41/51] x86/entry/unwind: create stack frames for saved interrupt registers Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:40 +0200
Re: [PATCH v3 41/51] x86/entry/unwind: create stack frames for saved interrupt registers Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 18:40 +0200
[PATCH v3 37/51] x86/stacktrace: convert save_stack_trace_*() to use the new unwinder Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 05/51] x86/dumpstack: make printk_stack_address() more generally useful Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 43/51] x86/dumpstack: print stack identifier on its own line Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 24/51] ftrace: only allocate the ret_stack 'fp' field when needed Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 29/51] x86/dumpstack/ftrace: mark function graph handler function as unreliable Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:40 +0200
[PATCH v3 03/51] x86/asm/head: rename 'stack_start' -> 'initial_stack' Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
[PATCH v3 09/51] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
Re: [PATCH v3 09/51] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:30 +0200
Re: [PATCH v3 09/51] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Brian Gerst <brgerst@gmail.com> - 2016-08-14 15:00 +0200
Re: [PATCH v3 09/51] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Andy Lutomirski <luto@amacapital.net> - 2016-08-14 15:50 +0200
Re: [PATCH v3 09/51] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 17:10 +0200
Re: [PATCH v3 09/51] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 19:30 +0200
Re: [PATCH v3 09/51] x86/dumpstack: fix x86_32 kernel_stack_pointer() previous stack access Andy Lutomirski <luto@amacapital.net> - 2016-08-15 22:10 +0200
[PATCH v3 13/51] x86/asm/head: remove useless zeroed word Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
[PATCH v3 21/51] oprofile/x86: add regs->ip to oprofile trace Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
[PATCH v3 10/51] x86/dumpstack: add get_stack_pointer() and get_frame_pointer() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
[PATCH v3 07/51] x86/dumpstack: remove extra brackets around "<EOE>" Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
[PATCH v3 17/51] x86/smp: fix initial idle stack location on 32-bit Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
[PATCH v3 08/51] x86/dumpstack: fix irq stack bounds calculation in show_stack_log_lvl() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
[PATCH v3 15/51] x86/asm/head: standardize the end of the stack for idle tasks Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
Re: [PATCH v3 15/51] x86/asm/head: standardize the end of the stack for idle tasks Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:40 +0200
[PATCH v3 19/51] x86/entry/32: rename 'error_code' to 'common_exception' Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
Re: [PATCH v3 19/51] x86/entry/32: rename 'error_code' to 'common_exception' Andy Lutomirski <luto@amacapital.net> - 2016-08-14 10:50 +0200
Re: [PATCH v3 19/51] x86/entry/32: rename 'error_code' to 'common_exception' Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-15 17:40 +0200
[PATCH v3 23/51] ftrace: remove CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST from config Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 16:50 +0200
[PATCH v3 11/51] x86/dumpstack: remove unnecessary stack pointer arguments Josh Poimboeuf <jpoimboe@redhat.com> - 2016-08-12 17:10 +0200
csiph-web