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| author |   Christophe Leroy <christophe.leroy@c-s.fr> | 2018-12-14 15:23:33 +0000 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2018-12-20 22:21:20 +1100 |
| commit | 49a502ea23bf9dec47f8f3c3960909ff409cd1bb (patch) | |
| tree | 40fafec29c2ab96304aa9bf666d099e0bc66bd70 /arch/powerpc/mm/fault.c | |
| parent | powerpc/ptrace: Combine SYSCALL_EMU & SYSCALL_TRACE handling (diff) | |
| download | linux-dev-49a502ea23bf9dec47f8f3c3960909ff409cd1bb.tar.xz linux-dev-49a502ea23bf9dec47f8f3c3960909ff409cd1bb.zip | |
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: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Avoid pr_cont()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm/fault.c')
| -rw-r--r-- | arch/powerpc/mm/fault.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index c448ca75f4b3..c866d9a710fe 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -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", |