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authorIlya Leoshkevich <iii@linux.ibm.com>2019-10-02 13:29:57 +0200
committerVasily Gorbik <gor@linux.ibm.com>2019-10-31 17:26:48 +0100
commita1d863ac3e1085e1fea9caafd87252d08731de2e (patch)
tree792a0fa48c6c5b0c061c3bdd082f6867c54665f0 /arch
parentb8e51a6a9db94bc1fb18ae831b3dab106b5a4b5f (diff)
s390/unwind: fix mixing regs and sp
unwind_for_each_frame stops after the first frame if regs->gprs[15] <= sp. The reason is that in case regs are specified, the first frame should be regs->psw.addr and the second frame should be sp->gprs[8]. However, currently the second frame is regs->gprs[15], which confuses outside_of_stack(). Fix by introducing a flag to distinguish this special case from unwinding the interrupt handler, for which the current behavior is appropriate. Fixes: 78c98f907413 ("s390/unwind: introduce stack unwind API") Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Cc: stable@vger.kernel.org # v5.2+ Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/include/asm/unwind.h1
-rw-r--r--arch/s390/kernel/unwind_bc.c18
2 files changed, 14 insertions, 5 deletions
diff --git a/arch/s390/include/asm/unwind.h b/arch/s390/include/asm/unwind.h
index d827b5b9a32c..eaaefeceef6f 100644
--- a/arch/s390/include/asm/unwind.h
+++ b/arch/s390/include/asm/unwind.h
@@ -35,6 +35,7 @@ struct unwind_state {
struct task_struct *task;
struct pt_regs *regs;
unsigned long sp, ip;
+ bool reuse_sp;
int graph_idx;
bool reliable;
bool error;
diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c
index 8fc9daae47a2..a8204f952315 100644
--- a/arch/s390/kernel/unwind_bc.c
+++ b/arch/s390/kernel/unwind_bc.c
@@ -46,10 +46,15 @@ bool unwind_next_frame(struct unwind_state *state)
regs = state->regs;
if (unlikely(regs)) {
- sp = READ_ONCE_NOCHECK(regs->gprs[15]);
- if (unlikely(outside_of_stack(state, sp))) {
- if (!update_stack_info(state, sp))
- goto out_err;
+ if (state->reuse_sp) {
+ sp = state->sp;
+ state->reuse_sp = false;
+ } else {
+ sp = READ_ONCE_NOCHECK(regs->gprs[15]);
+ if (unlikely(outside_of_stack(state, sp))) {
+ if (!update_stack_info(state, sp))
+ goto out_err;
+ }
}
sf = (struct stack_frame *) sp;
ip = READ_ONCE_NOCHECK(sf->gprs[8]);
@@ -107,9 +112,9 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
{
struct stack_info *info = &state->stack_info;
unsigned long *mask = &state->stack_mask;
+ bool reliable, reuse_sp;
struct stack_frame *sf;
unsigned long ip;
- bool reliable;
memset(state, 0, sizeof(*state));
state->task = task;
@@ -134,10 +139,12 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
if (regs) {
ip = READ_ONCE_NOCHECK(regs->psw.addr);
reliable = true;
+ reuse_sp = true;
} else {
sf = (struct stack_frame *) sp;
ip = READ_ONCE_NOCHECK(sf->gprs[8]);
reliable = false;
+ reuse_sp = false;
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -151,5 +158,6 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
state->sp = sp;
state->ip = ip;
state->reliable = reliable;
+ state->reuse_sp = reuse_sp;
}
EXPORT_SYMBOL_GPL(__unwind_start);