gam-server-0.1.10-ih_sub_cancel-deadlock.patch 2.0 KB

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  1. From cc14440eface093548cb3bc7814da11d9a99d283 Mon Sep 17 00:00:00 2001
  2. From: Anssi Hannula <anssi@mageia.org>
  3. Date: Wed, 4 Jan 2012 00:23:55 +0200
  4. Subject: [PATCH] fix possible server deadlock in ih_sub_cancel
  5. ih_sub_foreach() calls ih_sub_cancel() while inotify_lock is locked.
  6. However, ih_sub_cancel() locks it again, and locking GMutex recursively
  7. causes undefined behaviour.
  8. Fix that by removing locking from ih_sub_cancel() as ih_sub_foreach()
  9. is its only user. Also make the function static so that it won't
  10. accidentally get used by other files without locking (inotify-helper.h
  11. is an internal server header).
  12. This should fix the intermittent deadlocks I've been experiencing
  13. causing KDE applications to no longer start, and probably also
  14. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=542361
  15. ---
  16. server/inotify-helper.c | 7 ++-----
  17. server/inotify-helper.h | 1 -
  18. 2 files changed, 2 insertions(+), 6 deletions(-)
  19. diff --git a/server/inotify-helper.c b/server/inotify-helper.c
  20. index d77203e..0789fa4 100644
  21. --- a/server/inotify-helper.c
  22. +++ b/server/inotify-helper.c
  23. @@ -123,13 +123,11 @@ ih_sub_add (ih_sub_t * sub)
  24. /**
  25. * Cancels a subscription which was being monitored.
  26. + * inotify_lock must be held when calling.
  27. */
  28. -gboolean
  29. +static gboolean
  30. ih_sub_cancel (ih_sub_t * sub)
  31. {
  32. - G_LOCK(inotify_lock);
  33. -
  34. -
  35. if (!sub->cancelled)
  36. {
  37. IH_W("cancelling %s\n", sub->pathname);
  38. @@ -140,7 +138,6 @@ ih_sub_cancel (ih_sub_t * sub)
  39. sub_list = g_list_remove (sub_list, sub);
  40. }
  41. - G_UNLOCK(inotify_lock);
  42. return TRUE;
  43. }
  44. diff --git a/server/inotify-helper.h b/server/inotify-helper.h
  45. index 5d3b6d0..d36b5fd 100644
  46. --- a/server/inotify-helper.h
  47. +++ b/server/inotify-helper.h
  48. @@ -34,7 +34,6 @@ gboolean ih_startup (event_callback_t ecb,
  49. found_callback_t fcb);
  50. gboolean ih_running (void);
  51. gboolean ih_sub_add (ih_sub_t *sub);
  52. -gboolean ih_sub_cancel (ih_sub_t *sub);
  53. /* Return FALSE from 'f' if the subscription should be cancelled */
  54. void ih_sub_foreach (void *callerdata, gboolean (*f)(ih_sub_t *sub, void *callerdata));
  55. --
  56. 1.7.7.2