Commit 49a502ea authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/mm: Make NULL pointer deferences explicit on bad page faults. 



As several other arches including x86, this patch makes it explicit
that a bad page fault is a NULL pointer dereference when the fault
address is lower than PAGE_SIZE

In the mean time, this page makes all bad_page_fault() messages
shorter so that they remain on one single line. And it prefixes them
by "BUG: " so that they get easily grepped.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
[mpe: Avoid pr_cont()]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 8dbdec0b

arch/powerpc/mm/fault.c

+9 −8
Original line number Diff line number Diff line
@@ -650,21 +650,22 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) 
	switch (TRAP(regs)) {

	case 0x300:

	case 0x380:

		printk(KERN_ALERT "Unable to handle kernel paging request for "

			"data at address 0x%08lx\n", regs->dar);

		pr_alert("BUG: %s at 0x%08lx\n",

			 regs->dar < PAGE_SIZE ? "Kernel NULL pointer dereference" :

			 "Unable to handle kernel data access", regs->dar);

		break;

	case 0x400:

	case 0x480:

		printk(KERN_ALERT "Unable to handle kernel paging request for "

			"instruction fetch\n");

		pr_alert("BUG: Unable to handle kernel instruction fetch%s",

			 regs->nip < PAGE_SIZE ? " (NULL pointer?)\n" : "\n");

		break;

	case 0x600:

		printk(KERN_ALERT "Unable to handle kernel paging request for "

			"unaligned access at address 0x%08lx\n", regs->dar);

		pr_alert("BUG: Unable to handle kernel unaligned access at 0x%08lx\n",

			 regs->dar);

		break;

	default:

		printk(KERN_ALERT "Unable to handle kernel paging request for "

			"unknown fault\n");

		pr_alert("BUG: Unable to handle unknown paging fault at 0x%08lx\n",

			 regs->dar);

		break;

	}

	printk(KERN_ALERT "Faulting instruction address: 0x%08lx\n",

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