[PATCH] [9/23] PRINTK: Use stable variable to dump kmsg buffer
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From: Andi Kleen on 10 Jun 2010 07:20 kmsg_dump takes care to sample the global variables inside a spinlock, but then goes on to use the same variables outside the spinlock region too. Use the correct variable. This will make the race window smaller. Found by gcc 4.6's new warnings. Signed-off-by: Andi Kleen <ak(a)linux.intel.com> --- kernel/printk.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) Index: linux-2.6.35-rc2-gcc/kernel/printk.c =================================================================== --- linux-2.6.35-rc2-gcc.orig/kernel/printk.c +++ linux-2.6.35-rc2-gcc/kernel/printk.c @@ -1520,9 +1520,9 @@ void kmsg_dump(enum kmsg_dump_reason rea chars = logged_chars; spin_unlock_irqrestore(&logbuf_lock, flags); - if (logged_chars > end) { - s1 = log_buf + log_buf_len - logged_chars + end; - l1 = logged_chars - end; + if (chars > end) { + s1 = log_buf + log_buf_len - chars + end; + l1 = chars - end; s2 = log_buf; l2 = end; @@ -1530,8 +1530,8 @@ void kmsg_dump(enum kmsg_dump_reason rea s1 = ""; l1 = 0; - s2 = log_buf + end - logged_chars; - l2 = logged_chars; + s2 = log_buf + end - chars; + l2 = chars; } if (!spin_trylock_irqsave(&dump_list_lock, flags)) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |