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powerpc: Fix BUG_ON() reporting in real mode

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I ran into this issue while debugging an early boot problem. The system
hit a BUG_ON() but report bug failed to print the line number and file
name. The reason being that the system was running in real mode and
report_bug() searches for addresses in the PAGE_OFFSET+ region.

Suggested-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Balbir Singh 2016-02-18 13:48:01 +11:00 committed by Michael Ellerman
parent 10d8b1480e
commit a4c3f909b4
1 changed files with 9 additions and 1 deletions
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10
arch/powerpc/kernel/traps.c
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@ -1148,6 +1148,7 @@ void __kprobes program_check_exception(struct pt_regs *regs)
goto bail;
}
if (reason & REASON_TRAP) {
unsigned long bugaddr;
/* Debugger is first in line to stop recursive faults in
* rcu_lock, notify_die, or atomic_notifier_call_chain */
if (debugger_bpt(regs))
@ -1158,8 +1159,15 @@ void __kprobes program_check_exception(struct pt_regs *regs)
== NOTIFY_STOP)
goto bail;
bugaddr = regs->nip;
/*
* Fixup bugaddr for BUG_ON() in real mode
*/
if (!is_kernel_addr(bugaddr) && !(regs->msr & MSR_IR))
bugaddr += PAGE_OFFSET;
if (!(regs->msr & MSR_PR) && /* not user-mode */
report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) {
regs->nip += 4;
goto bail;
}