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authorRobin Getz <rgetz@blackfin.uclinux.org>2008-03-26 09:15:58 +0800
committerBryan Wu <cooloney@kernel.org>2008-03-26 09:15:58 +0800
commit9a62ca40fd793742f92565104c6b44319af8c282 (patch)
tree6f35dc65b76e9d789da6dc6ca72624adbc389f41 /arch/blackfin/kernel
parent81d9c7f27dd679df6d03df53eba4fd12caafdb47 (diff)
[Blackfin] arch: fix bug - when we crash, current is not valid
Sometimes when we crash, current is not valid, (has been written over), so the existing code causes a invalid read during exception context - which is a unrecoverable double fault. This fixes this. Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org> Signed-off-by: Bryan Wu <cooloney@kernel.org>
Diffstat (limited to 'arch/blackfin/kernel')
-rw-r--r--arch/blackfin/kernel/traps.c37
1 files changed, 23 insertions, 14 deletions
diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index e8e8f735c23..7557d0dce21 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -655,21 +655,30 @@ void dump_bfin_process(struct pt_regs *fp)
else if (context & 0x8000)
printk(KERN_NOTICE "Kernel process context\n");
- if (current->pid && current->mm) {
+ /* Because we are crashing, and pointers could be bad, we check things
+ * pretty closely before we use them
+ */
+ if (!((unsigned long)current & 0x3) && current->pid) {
printk(KERN_NOTICE "CURRENT PROCESS:\n");
- printk(KERN_NOTICE "COMM=%s PID=%d\n",
- current->comm, current->pid);
-
- printk(KERN_NOTICE "TEXT = 0x%p-0x%p DATA = 0x%p-0x%p\n"
- KERN_NOTICE "BSS = 0x%p-0x%p USER-STACK = 0x%p\n"
- KERN_NOTICE "\n",
- (void *)current->mm->start_code,
- (void *)current->mm->end_code,
- (void *)current->mm->start_data,
- (void *)current->mm->end_data,
- (void *)current->mm->end_data,
- (void *)current->mm->brk,
- (void *)current->mm->start_stack);
+ if (current->comm >= (char *)FIXED_CODE_START)
+ printk(KERN_NOTICE "COMM=%s PID=%d\n",
+ current->comm, current->pid);
+ else
+ printk(KERN_NOTICE "COMM= invalid\n");
+
+ if (!((unsigned long)current->mm & 0x3) && (unsigned long)current->mm >= FIXED_CODE_START)
+ printk(KERN_NOTICE "TEXT = 0x%p-0x%p DATA = 0x%p-0x%p\n"
+ KERN_NOTICE " BSS = 0x%p-0x%p USER-STACK = 0x%p\n"
+ KERN_NOTICE "\n",
+ (void *)current->mm->start_code,
+ (void *)current->mm->end_code,
+ (void *)current->mm->start_data,
+ (void *)current->mm->end_data,
+ (void *)current->mm->end_data,
+ (void *)current->mm->brk,
+ (void *)current->mm->start_stack);
+ else
+ printk(KERN_NOTICE "invalid mm\n");
} else
printk(KERN_NOTICE "\n" KERN_NOTICE
"No Valid process in current context\n");