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Subject[PATCH UPDATED] printk: fix possible printk buffer overrun introduced with recursion check
printk recursion detection prepends message to printk_buf and offsets
printk_buf when actual message is printed but it forgets to trim
buffer length accordingly. This can result in buffer overrun in
extreme cases. Fix it.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
---
Splitted out fix portion.
kernel/printk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/printk.c b/kernel/printk.c
index bee3610..9adc2a4 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -666,7 +666,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
}
/* Emit the output into the temporary buffer */
printed_len += vscnprintf(printk_buf + printed_len,
- sizeof(printk_buf), fmt, args);
+ sizeof(printk_buf) - printed_len, fmt, args);

/*
* Copy the output into log_buf. If the caller didn't provide

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