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Subject[PATCH] tile: don't call show_regs_print_info() with corrupt current
We use the validate_current() API to make sure that "current" seems
plausible before using it. With the new show_regs_print_info()
API, we want to check that current is OK before calling it, since
otherwise we will end up in a recursive panic.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
---
arch/tile/kernel/process.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 663289b..44cdc4a 100644
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -226,19 +226,20 @@ int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
(unsigned int __user *)adr);
}

+static struct task_struct corrupt_current = { .comm = "<corrupt>" };
+
/*
* Return "current" if it looks plausible, or else a pointer to a dummy.
* This can be helpful if we are just trying to emit a clean panic.
*/
struct task_struct *validate_current(void)
{
- static struct task_struct corrupt = { .comm = "<corrupt>" };
struct task_struct *tsk = current;
if (unlikely((unsigned long)tsk < PAGE_OFFSET ||
(high_memory && (void *)tsk > high_memory) ||
((unsigned long)tsk & (__alignof__(*tsk) - 1)) != 0)) {
pr_err("Corrupt 'current' %p (sp %#lx)\n", tsk, stack_pointer);
- tsk = &corrupt;
+ tsk = &corrupt_current;
}
return tsk;
}
@@ -589,7 +590,8 @@ void show_regs(struct pt_regs *regs)
int i;

pr_err("\n");
- show_regs_print_info(KERN_ERR);
+ if (tsk != &corrupt_current)
+ show_regs_print_info(KERN_ERR);
#ifdef __tilegx__
for (i = 0; i < 17; i++)
pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
--
1.8.3.1


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