From e19af3803be804f2737788e62d243e425bb03011 Mon Sep 17 00:00:00 2001 From: Pino Toscano Date: Mon, 19 Nov 2012 20:01:00 +0100 Subject: muntrace: reset file and hooks before finalizing the stream fclose will call free, invoking its hook, then fprintf which would indirectly try to allocate a buffer, and this can cause malloc to be used (thus its hook to be invoked) if libio uses malloc instead of mmap; given any malloc/free hook locks the internal lock, this leads to a deadlock. To prevent this hook roundtrip at muntrace, first unset MALLSTREAM and the hooks, and only after that close the trace file. --- ChangeLog | 3 +++ malloc/mtrace.c | 9 +++++++-- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index fbac1c5d5d..1031d4d5c1 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,8 @@ 2012-11-19 Pino Toscano + * malloc/mtrace.c (muntrace): Reset MALLSTREAM and the hooks before + finalizing MALLSTREAM. + * sysdeps/mach/hurd/syncfs.c: New file. 2012-11-19 Siddhesh Poyarekar diff --git a/malloc/mtrace.c b/malloc/mtrace.c index d7a032a86a..3f02c71822 100644 --- a/malloc/mtrace.c +++ b/malloc/mtrace.c @@ -364,11 +364,16 @@ muntrace () if (mallstream == NULL) return; - fprintf (mallstream, "= End\n"); - fclose (mallstream); + /* Do the reverse of what done in mtrace: first reset the hooks and + MALLSTREAM, and only after that write the trailer and close the + file. */ + FILE *f = mallstream; mallstream = NULL; __free_hook = tr_old_free_hook; __malloc_hook = tr_old_malloc_hook; __realloc_hook = tr_old_realloc_hook; __memalign_hook = tr_old_memalign_hook; + + fprintf (f, "= End\n"); + fclose (f); } -- cgit v1.2.3