diff options
| author |   Mark Rutland <mark.rutland@arm.com> | 2016-11-03 20:23:08 +0000 |
|---|---|---|
| committer |   Catalin Marinas <catalin.marinas@arm.com> | 2016-11-11 18:25:44 +0000 |
| commit | 9bbd4c56b0b642f04396da378296e68096d5afca (patch) | |
| tree | 3748f98d16c323a04cf7c6dd208b2fc80bf311f8 /arch/arm64/kernel/traps.c | |
| parent | arm64: unexport walk_stackframe (diff) | |
| download | linux-dev-9bbd4c56b0b642f04396da378296e68096d5afca.tar.xz linux-dev-9bbd4c56b0b642f04396da378296e68096d5afca.zip | |
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 '')
| -rw-r--r-- | arch/arm64/kernel/traps.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 7ac30bf943e9..4731133286b3 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -148,6 +148,9 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) if (!tsk) tsk = current; + if (!try_get_task_stack(tsk)) + return; + /* * Switching between stacks is valid when tracing current and in * non-preemptible context. @@ -213,6 +216,8 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) stack + sizeof(struct pt_regs)); } } + + put_task_stack(tsk); } void show_stack(struct task_struct *tsk, unsigned long *sp) |