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[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>
This commit is contained in:
Robin Getz 2008-03-26 09:15:58 +08:00 committed by Bryan Wu
parent 81d9c7f27d
commit 9a62ca40fd
1 changed files with 22 additions and 13 deletions
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35
arch/blackfin/kernel/traps.c
View File

@ -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);
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");
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 (!((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");