linux-kernel - panic doesn't get invoked on oops when panic_on

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Message-ID: <CACBffj90HufSBwL5fcmCzLjvQJ_QOMfT=3KJgbkgjn55kudwNw@mail.gmail.com>
Date:	Fri, 30 Nov 2012 17:03:53 +0530
From:	Kalash Nainwal <kalash@...stanetworks.com>
To:	linux-kernel@...r.kernel.org
Cc:	Kalash Nainwal <kalash@...stanetworks.com>
Subject: panic doesn't get invoked on oops when panic_on_oops is set

Hi,

An oops doesn't result in panic() call even when panic_on_oops
is set (if we've a crash kernel loaded). The reason seems to be
that from oops codepath before calling panic(), we call
crash_kexec() if panic_on_oops is set:

void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)

{
       if (regs && kexec_should_crash(current))
                crash_kexec(regs);  <====== I'm hitting this
        .
        .
        if (panic_on_oops)
                 panic("Fatal exception");  <==== I want this to be hit
        do_exit(signr);
}

int kexec_should_crash(struct task_struct *p)
{
          if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
                   return 1;
           return 0;
}

If we let panic() get called from oops_end(), we would eventually
call crash_kexec() from panic() anyway. Isn't it?

Then is the panic_on_oops check in kexec_should_crash()
redundant? Or there's reason behind this behavior?

Would greatly appreciate any response here. Also please CC me
as I am not part of linux-kernel list.

Regards,
-Kalash
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