Messages in this thread |  | | | Date | Fri, 19 Dec 2008 23:35:58 +0100 | | From | Ingo Molnar <> | | Subject | Re: [PATCH] printk: fix discarding message when recursion_bug |
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* Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> wrote:
> Ingo Molnar wrote: > > * Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> wrote: > > > >> From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> > >> > >> Impact: fix > >> > >> When recursion_bug is true, kernel discards original message because printk_buf > >> contains recursion_bug_msg with NULL terminator. The sizeof(recursion_bug_msg) > >> makes this, use strlen() to get correct length without NULL terminator. > >> > >> Reported-by: Toshikazu Nakayama <nakayama.ts@ncos.nec.co.jp> > >> Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> > >> --- > >> kernel/printk.c | 2 +- > >> 1 files changed, 1 insertions(+), 1 deletions(-) > > > > Good one - applied to tip/core/printk, thanks! > > > > Btw., i'm curious: in what situation was such recursion observed, and how > > did the kernel behave? You saw a truncated recursion message in dmesg - or > > was it worse? > > I'm not sure about the real situation. I've heard this issue was found > in printing messages in NMI handler, maybe with artificial kernel stuck.
yeah, accidental NMI recursion back into printk could indeed cause the recursion message to pop up.
Ingo
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