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Groups > linux.kernel > #1482790
| From | Andy Lutomirski <luto@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 09/12] x86/process: Pin the target stack in get_wchan() |
| Date | 2016-09-13 23:40 +0200 |
| Message-ID | <sh3AS-7tK-23@gated-at.bofh.it> (permalink) |
| References | <sh3rc-7o2-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
This will prevent a crash if get_wchan() runs after the task stack
is freed.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/kernel/process.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 0b9ed8ec5226..4002b475171c 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -532,15 +532,18 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
*/
unsigned long get_wchan(struct task_struct *p)
{
- unsigned long start, bottom, top, sp, fp, ip;
+ unsigned long start, bottom, top, sp, fp, ip, ret = 0;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
+ if (!try_get_task_stack(p))
+ return 0;
+
start = (unsigned long)task_stack_page(p);
if (!start)
- return 0;
+ goto out;
/*
* Layout of the stack page:
@@ -564,16 +567,21 @@ unsigned long get_wchan(struct task_struct *p)
sp = READ_ONCE(p->thread.sp);
if (sp < bottom || sp > top)
- return 0;
+ goto out;
fp = READ_ONCE_NOCHECK(((struct inactive_task_frame *)sp)->bp);
do {
if (fp < bottom || fp > top)
- return 0;
+ goto out;
ip = READ_ONCE_NOCHECK(*(unsigned long *)(fp + sizeof(unsigned long)));
- if (!in_sched_functions(ip))
- return ip;
+ if (!in_sched_functions(ip)) {
+ ret = ip;
+ goto out;
+ }
fp = READ_ONCE_NOCHECK(*(unsigned long *)fp);
} while (count++ < 16 && p->state != TASK_RUNNING);
- return 0;
+
+out:
+ put_task_stack(p);
+ return ret;
}
--
2.7.4
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[PATCH 00/12] thread_info cleanups and stack caching Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:30 +0200
[PATCH 03/12] um: Stop conflating task_struct::stack with thread_info Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:30 +0200
Re: [PATCH 03/12] um: Stop conflating task_struct::stack with thread_info Ingo Molnar <mingo@kernel.org> - 2016-09-15 08:30 +0200
[tip:x86/asm] um/Stop conflating task_struct::stack with thread_info tip-bot for Linus Torvalds <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 12/12] fork: Cache two thread stacks per cpu if CONFIG_VMAP_STACK is set Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[PATCH 01/12] x86/asm: Move 'status' from struct thread_info to struct thread_struct Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[tip:x86/asm] x86/asm: Move the thread_info::status field to thread_struct tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 10/12] lib/syscall: Pin the task stack in collect_syscall() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-09-14 17:00 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@amacapital.net> - 2016-09-14 20:30 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-09-14 20:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@amacapital.net> - 2016-09-15 20:10 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-09-15 20:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@amacapital.net> - 2016-09-15 20:50 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Josh Poimboeuf <jpoimboe@redhat.com> - 2016-09-15 21:20 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Peter Zijlstra <peterz@infradead.org> - 2016-09-16 09:50 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@amacapital.net> - 2016-09-16 17:20 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski <luto@kernel.org> - 2016-09-16 17:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Peter Zijlstra <peterz@infradead.org> - 2016-09-16 18:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Peter Zijlstra <peterz@infradead.org> - 2016-09-16 17:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Ingo Molnar <mingo@kernel.org> - 2016-09-15 08:40 +0200
Re: [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Ingo Molnar <mingo@kernel.org> - 2016-09-15 11:30 +0200
[PATCH 09/12] x86/process: Pin the target stack in get_wchan() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
Re: [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Jann Horn <jann@thejh.net> - 2016-09-17 04:10 +0200
Re: [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Andy Lutomirski <luto@amacapital.net> - 2016-09-23 00:50 +0200
Re: [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Andy Lutomirski <luto@amacapital.net> - 2016-09-23 01:00 +0200
Re: [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Jann Horn <jann@thejh.net> - 2016-09-23 09:50 +0200
[PATCH 06/12] sched: Add try_get_task_stack() and put_task_stack() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[PATCH 02/12] x86/entry: Get rid of pt_regs_to_thread_info() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
Re: [PATCH 02/12] x86/entry: Get rid of pt_regs_to_thread_info() Ingo Molnar <mingo@kernel.org> - 2016-09-15 08:30 +0200
[tip:x86/asm] x86/entry: Get rid of pt_regs_to_thread_info() tip-bot for Linus Torvalds <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 05/12] x86: Move thread_info into task_struct Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[tip:x86/asm] x86: Move thread_info into task_struct tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 04/12] sched: Allow putting thread_info into task_struct Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[tip:x86/asm] sched/core: Allow putting thread_info into task_struct tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-09-15 12:50 +0200
[PATCH 11/12] sched: Free the stack early if CONFIG_THREAD_INFO_IN_TASK Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
[PATCH 07/12] kthread: to_live_kthread() needs try_get_task_stack() Andy Lutomirski <luto@kernel.org> - 2016-09-13 23:40 +0200
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