[PATCH] powerpc/mm: make NULL pointer deferences explicit on bad page faults.
From: Christophe Leroy <hidden>
Date: 2018-10-09 05:21:37
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
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 Signed-off-by: Christophe Leroy <redacted> --- arch/powerpc/mm/fault.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index d51cf5f4e45e..501a1eadb3e9 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c@@ -631,13 +631,16 @@ 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("Unable to handle kernel %s for data at address 0x%08lx\n", + regs->dar < PAGE_SIZE ? "NULL pointer dereference" : + "paging request", + regs->dar); break; case 0x400: case 0x480: - printk(KERN_ALERT "Unable to handle kernel paging request for " - "instruction fetch\n"); + pr_alert("Unable to handle kernel %s for instruction fetch\n", + regs->nip < PAGE_SIZE ? "NULL pointer dereference" : + "paging request"); break; case 0x600: printk(KERN_ALERT "Unable to handle kernel paging request for "
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2.13.3