Skip to content
Commit 5cf045f5 authored by Alistair Strachan's avatar Alistair Strachan Committed by Greg Kroah-Hartman
Browse files

staging: sync: Fix a race condition between release_obj and print_obj



Before this change, a timeline would only be removed from the timeline
list *after* the sync driver had its release_obj() called. However, the
driver's release_obj() may free resources needed by print_obj().

Although the timeline list is locked when print_obj() is called, it is
not locked when release_obj() is called. If one CPU was in print_obj()
when another was in release_obj(), the print_obj() may make unsafe
accesses.

It is not actually necessary to hold the timeline list lock when calling
release_obj() if the call is made after the timeline is unlinked from
the list, since there is no possibility another thread could be in --
or enter -- print_obj() for that timeline.

This change moves the release_obj() call to after the timeline is
unlinked, preventing the above race from occurring.

Cc: Colin Cross <ccross@android.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: default avatarAlistair Strachan <alistair.strachan@imgtec.com>
[jstultz: minor commit subject tweak]
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bbd9ae8a
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment