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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2018-12-14 15:23:33 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-05 15:26:58 +0100 |
| commit | 5855158b884ab9859c1b6284954beaf36822509e (patch) | |
| tree | c82122f9b119d3a8fb71f3cc9b61767a324e0028 /arch | |
| parent | b3e9c6c877622c6a1a6ccf7879af49850cc24cde (diff) | |
| download | linux-stable-5855158b884ab9859c1b6284954beaf36822509e.tar.gz linux-stable-5855158b884ab9859c1b6284954beaf36822509e.tar.bz2 linux-stable-5855158b884ab9859c1b6284954beaf36822509e.zip | |
powerpc/mm: Make NULL pointer deferences explicit on bad page faults.
[ Upstream commit 49a502ea23bf9dec47f8f3c3960909ff409cd1bb ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
| -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 d154e333f76b..d1f860ca03ad 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -521,21 +521,22 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) switch (regs->trap) { 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", |