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| author |   Vasily Gorbik <gor@linux.ibm.com> | 2019-11-22 16:49:13 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2019-11-30 10:52:45 +0100 |
| commit | e76e69611e944ecc38aaf8fe3a7bebdc3c5daf84 (patch) | |
| tree | 0f57673f7fb9e0464b6985735009b8425a1541af /arch/s390/kernel/unwind_bc.c | |
| parent | s390/head64: correct init_task stack setup (diff) | |
| download | linux-dev-e76e69611e944ecc38aaf8fe3a7bebdc3c5daf84.tar.xz linux-dev-e76e69611e944ecc38aaf8fe3a7bebdc3c5daf84.zip | |
s390/unwind: stop gracefully at task pt_regs
Consider reaching task pt_regs graceful unwinder termination. Task
pt_regs itself never contains a valid state to which a task might return
within the kernel context (user task pt_regs is a special case). Since
we already avoid printing user task pt_regs and in most cases we don't
even bother filling task pt_regs psw and r15 with something reasonable
simply skip task pt_regs altogether. With this change unwind_error() now
accurately represent whether unwinder reached task pt_regs successfully
or failed along the way.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/kernel/unwind_bc.c')
| -rw-r--r-- | arch/s390/kernel/unwind_bc.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c index ac6cfab567d1..c5ebb8a4cdd6 100644 --- a/arch/s390/kernel/unwind_bc.c +++ b/arch/s390/kernel/unwind_bc.c @@ -36,6 +36,12 @@ 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) +{ + return task_pt_regs(state->task) == regs; +} + bool unwind_next_frame(struct unwind_state *state) { struct stack_info *info = &state->stack_info; @@ -69,7 +75,7 @@ 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 (READ_ONCE_NOCHECK(regs->psw.mask) & PSW_MASK_PSTATE) + if (is_task_pt_regs(state, regs)) goto out_stop; ip = READ_ONCE_NOCHECK(regs->psw.addr); sp = READ_ONCE_NOCHECK(regs->gprs[15]); |