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authorVasily Gorbik2019-12-11 17:27:31 +0100
committerVasily Gorbik2019-12-18 23:29:26 +0100
commiteef06cbf670aaa2ccb56c9a7b84042acd657aa5d (patch)
treed7ec3302b9c80e67babb6e27dddc79b28b1508c5 /arch/s390
parentc23587c92f6e3260fe3b82bb75b38aa2553b9468 (diff)
s390/unwind: stop gracefully at user mode pt_regs in irq stack
Consider reaching user mode pt_regs at the bottom of irq stack graceful unwinder termination. This is the case when irq/mcck/ext interrupt arrives while in user mode. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/unwind_bc.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c
index da2d4d4c5b0e..707fd99f6734 100644
--- a/arch/s390/kernel/unwind_bc.c
+++ b/arch/s390/kernel/unwind_bc.c
@@ -36,10 +36,17 @@ static bool update_stack_info(struct unwind_state *state, unsigned long sp)
return true;
}
-static inline bool is_task_pt_regs(struct unwind_state *state,
- struct pt_regs *regs)
+static inline bool is_final_pt_regs(struct unwind_state *state,
+ struct pt_regs *regs)
{
- return task_pt_regs(state->task) == regs;
+ /* user mode or kernel thread pt_regs at the bottom of task stack */
+ if (task_pt_regs(state->task) == regs)
+ return true;
+
+ /* user mode pt_regs at the bottom of irq stack */
+ return state->stack_info.type == STACK_TYPE_IRQ &&
+ state->stack_info.end - sizeof(struct pt_regs) == (unsigned long)regs &&
+ READ_ONCE_NOCHECK(regs->psw.mask) & PSW_MASK_PSTATE;
}
bool unwind_next_frame(struct unwind_state *state)
@@ -80,7 +87,7 @@ bool unwind_next_frame(struct unwind_state *state)
if (!on_stack(info, sp, sizeof(struct pt_regs)))
goto out_err;
regs = (struct pt_regs *) sp;
- if (is_task_pt_regs(state, regs))
+ if (is_final_pt_regs(state, regs))
goto out_stop;
ip = READ_ONCE_NOCHECK(regs->psw.addr);
sp = READ_ONCE_NOCHECK(regs->gprs[15]);