Commit 84c6c2af authored by Will Deacon's avatar Will Deacon Committed by Greg Kroah-Hartman

arm64: backtrace: Don't bother trying to unwind the userspace stack

commit 1e6f5440 upstream.

Calling dump_backtrace() with a pt_regs argument corresponding to
userspace doesn't make any sense and our unwinder will simply print
"Call trace:" before unwinding the stack looking for user frames.

Rather than go through this song and dance, just return early if we're
passed a user register state.

Cc: <stable@vger.kernel.org>
Fixes: 1149aad1 ("arm64: Add dump_backtrace() in show_regs")
Reported-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1ec54cee
......@@ -101,10 +101,16 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
{
struct stackframe frame;
int skip;
int skip = 0;
pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
if (regs) {
if (user_mode(regs))
return;
skip = 1;
}
if (!tsk)
tsk = current;
......@@ -125,7 +131,6 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
frame.graph = tsk->curr_ret_stack;
#endif
skip = !!regs;
printk("Call trace:\n");
do {
/* skip until specified stack frame */
......@@ -175,15 +180,13 @@ static int __die(const char *str, int err, struct pt_regs *regs)
return ret;
print_modules();
__show_regs(regs);
pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
end_of_stack(tsk));
show_regs(regs);
if (!user_mode(regs)) {
dump_backtrace(regs, tsk);
if (!user_mode(regs))
dump_instr(KERN_EMERG, regs);
}
return ret;
}
......
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