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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-11 15:30:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-11 15:30:05 -0700
commitdb0457338ece7482378d88e50ad298191c3e6947 (patch)
tree459378b5005622cdf9b3bccfb798229c20aa41a2 /kernel
parent1f7563f743d7081710a9d186a8b203997d09f383 (diff)
parent38195dd5e916f3e55aec585703f2432562c2db02 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching
Pull livepatching updates from Jiri Kosina: - stacktrace handling improvements from Miroslav benes - debug output improvements from Petr Mladek * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching: livepatch: Remove duplicate warning about missing reliable stacktrace support Revert "livepatch: Remove reliable stacktrace check in klp_try_switch_task()" stacktrace: Remove weak version of save_stack_trace_tsk_reliable() livepatch: Use static buffer for debugging messages under rq lock livepatch: Remove stale kobj_added entries from kernel-doc descriptions
Diffstat (limited to 'kernel')
-rw-r--r--kernel/livepatch/transition.c11
-rw-r--r--kernel/stacktrace.c8
2 files changed, 8 insertions, 11 deletions
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index abb2a4a2cbb2..cdf318d86dd6 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -247,7 +247,6 @@ static int klp_check_stack(struct task_struct *task, char *err_buf)
int ret, nr_entries;
ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries));
- WARN_ON_ONCE(ret == -ENOSYS);
if (ret < 0) {
snprintf(err_buf, STACK_ERR_BUF_SIZE,
"%s: %s:%d has an unreliable stack\n",
@@ -281,11 +280,11 @@ static int klp_check_stack(struct task_struct *task, char *err_buf)
*/
static bool klp_try_switch_task(struct task_struct *task)
{
+ static char err_buf[STACK_ERR_BUF_SIZE];
struct rq *rq;
struct rq_flags flags;
int ret;
bool success = false;
- char err_buf[STACK_ERR_BUF_SIZE];
err_buf[0] = '\0';
@@ -294,6 +293,13 @@ static bool klp_try_switch_task(struct task_struct *task)
return true;
/*
+ * For arches which don't have reliable stack traces, we have to rely
+ * on other methods (e.g., switching tasks at kernel exit).
+ */
+ if (!klp_have_reliable_stack())
+ return false;
+
+ /*
* Now try to check the stack for any to-be-patched or to-be-unpatched
* functions. If all goes well, switch the task to the target patch
* state.
@@ -328,7 +334,6 @@ done:
pr_debug("%s", err_buf);
return success;
-
}
/*
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index c8d0f05721a1..e6a02b274b73 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -255,14 +255,6 @@ save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
}
-__weak int
-save_stack_trace_tsk_reliable(struct task_struct *tsk,
- struct stack_trace *trace)
-{
- WARN_ONCE(1, KERN_INFO "save_stack_tsk_reliable() not implemented yet.\n");
- return -ENOSYS;
-}
-
/**
* stack_trace_save - Save a stack trace into a storage array
* @store: Pointer to storage array

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