79 lines
1.8 KiB
Diff
79 lines
1.8 KiB
Diff
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From 05c3f60fe02370f4c8d15b996bcc8d6f3dc57e12 Mon Sep 17 00:00:00 2001
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From: Ludwig Nussel <ludwig.nussel@suse.de>
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Date: Thu, 21 Jun 2012 09:09:19 +0200
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Subject: [PATCH] fix deadlock
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writelog() must not call pthread_yield() with the lock held that the
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main thread tries to get to cancel the writer thread. writelog()
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on the other hand needs to empty the buffer always to make sure
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poll() blocks again an doesn't cause a loop.
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---
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libconsole.c | 25 +++++++++++++++++--------
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1 files changed, 17 insertions(+), 8 deletions(-)
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diff --git a/libconsole.c b/libconsole.c
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index b962032..54b353a 100644
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--- a/libconsole.c
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+++ b/libconsole.c
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@@ -429,21 +429,28 @@ xout:
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static inline void writelog(void)
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{
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- if (!flog)
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+ lock(&llock);
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+ if (!flog) { /* log file closed, reset buffer */
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+ resetlog();
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+ unlock(&llock);
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return;
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+ }
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clearerr(flog);
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- lock(&llock);
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while (avail > 0) {
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size_t ret = (size_t)avail;
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if (avail > TRANS_BUFFER_SIZE)
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ret = TRANS_BUFFER_SIZE;
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- if (!flog || nsigsys)
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+ if (!flog || nsigsys) { /* log file closed, reset buffer */
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+ resetlog();
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break;
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+ }
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ret = fwrite(head, sizeof(unsigned char), ret, flog);
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- if (!ret && ferror(flog))
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+ if (!ret && ferror(flog)) { /* cannot write anymore, reset buffer */
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+ resetlog();
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break;
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+ }
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head += ret;
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if (head >= tail) { /* empty, reset buffer */
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@@ -498,8 +505,13 @@ static inline int poll(int msec, mutex_t *outer)
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if (err == ETIMEDOUT || err == EBUSY)
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ret = 0;
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}
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- } else
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+#if 0
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+ } else {
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+ unlock(&ljoin);
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pthread_yield();
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+ lock(&ljoin);
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+#endif
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+ }
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return ret;
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}
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@@ -772,9 +784,6 @@ static void *action(void *dummy attribute((unused)))
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if (!poll(30, &ljoin))
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continue;
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- if (!flog)
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- break;
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-
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writelog();
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}
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unlock(&ljoin);
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--
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1.7.7
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