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| author | Mark Rutland <mark.rutland@arm.com> | 2016-11-03 23:23:08 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2016-11-11 21:25:44 +0300 |
| commit | 9bbd4c56b0b642f04396da378296e68096d5afca (patch) | |
| tree | 3748f98d16c323a04cf7c6dd208b2fc80bf311f8 /arch/arm64/kernel/stacktrace.c | |
| parent | 2020a5ae7c8c2c8504565004915017507b135c63 (diff) | |
| download | linux-9bbd4c56b0b642f04396da378296e68096d5afca.tar.xz | |
arm64: prep stack walkers for THREAD_INFO_IN_TASK
When CONFIG_THREAD_INFO_IN_TASK is selected, task stacks may be freed
before a task is destroyed. To account for this, the stacks are
refcounted, and when manipulating the stack of another task, it is
necessary to get/put the stack to ensure it isn't freed and/or re-used
while we do so.
This patch reworks the arm64 stack walking code to account for this.
When CONFIG_THREAD_INFO_IN_TASK is not selected these perform no
refcounting, and this should only be a structural change that does not
affect behaviour.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/stacktrace.c')
| -rw-r--r-- | arch/arm64/kernel/stacktrace.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index d53f99d4c223..8a552a33c6ef 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -181,6 +181,9 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) struct stack_trace_data data; struct stackframe frame; + if (!try_get_task_stack(tsk)) + return; + data.trace = trace; data.skip = trace->skip; @@ -202,6 +205,8 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) walk_stackframe(tsk, &frame, save_trace, &data); if (trace->nr_entries < trace->max_entries) trace->entries[trace->nr_entries++] = ULONG_MAX; + + put_task_stack(tsk); } void save_stack_trace(struct stack_trace *trace) |