From: Bart Van Assche <bvanassche@acm.org>
Date: Sun, 25 Mar 2012 17:51:59 +0000 (+0000)
Subject: Check whether the big lock is held before invoking pre_thread_ll_create.
X-Git-Tag: svn/VALGRIND_3_8_0~395
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=563f0acd21927a4efd9841cc8aa5da7cbaefce62;p=thirdparty%2Fvalgrind.git

Check whether the big lock is held before invoking pre_thread_ll_create.

If the pre_thread_ll_create tracking function would be invoked without the
big lock being held, that would trigger a race condition in the tools that
implement this tracking function.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12458
---

diff --git a/coregrind/m_scheduler/scheduler.c b/coregrind/m_scheduler/scheduler.c
index 4548db0a0a..be2ae59066 100644
--- a/coregrind/m_scheduler/scheduler.c
+++ b/coregrind/m_scheduler/scheduler.c
@@ -326,6 +326,12 @@ void VG_(release_BigLock_LL) ( HChar* who )
    ML_(release_sched_lock)(the_BigLock);
 }
 
+Bool VG_(owns_BigLock_LL) ( ThreadId tid )
+{
+   return (ML_(get_sched_lock_owner)(the_BigLock)
+           == VG_(threads)[tid].os_state.lwpid);
+}
+
 
 /* Clear out the ThreadState and release the semaphore. Leaves the
    ThreadState in VgTs_Zombie state, so that it doesn't get
diff --git a/coregrind/m_syswrap/syswrap-amd64-linux.c b/coregrind/m_syswrap/syswrap-amd64-linux.c
index 6408185d09..39a69484dc 100644
--- a/coregrind/m_syswrap/syswrap-amd64-linux.c
+++ b/coregrind/m_syswrap/syswrap-amd64-linux.c
@@ -289,6 +289,7 @@ static SysRes do_clone ( ThreadId ptid,
       know that this thread has come into existence.  If the clone
       fails, we'll send out a ll_exit notification for it at the out:
       label below, to clean up. */
+   vg_assert(VG_(owns_BigLock_LL)(ptid));
    VG_TRACK ( pre_thread_ll_create, ptid, ctid );
 
    if (flags & VKI_CLONE_SETTLS) {
diff --git a/coregrind/m_syswrap/syswrap-arm-linux.c b/coregrind/m_syswrap/syswrap-arm-linux.c
index 4c1137fb6c..a416b1169e 100644
--- a/coregrind/m_syswrap/syswrap-arm-linux.c
+++ b/coregrind/m_syswrap/syswrap-arm-linux.c
@@ -228,6 +228,7 @@ static SysRes do_clone ( ThreadId ptid,
       ctst->client_stack_szB  = 0;
    }
 
+   vg_assert(VG_(owns_BigLock_LL)(ptid));
    VG_TRACK ( pre_thread_ll_create, ptid, ctid );
 
    if (flags & VKI_CLONE_SETTLS) {
diff --git a/coregrind/m_syswrap/syswrap-darwin.c b/coregrind/m_syswrap/syswrap-darwin.c
index 96a83571ee..a6db239837 100644
--- a/coregrind/m_syswrap/syswrap-darwin.c
+++ b/coregrind/m_syswrap/syswrap-darwin.c
@@ -6483,6 +6483,7 @@ POST(bsdthread_create)
    // should be in pthread_hijack instead, just before the call to
    // start_thread_NORETURN(), call_on_new_stack_0_1(), but we don't have the
    // parent tid value there...
+   vg_assert(VG_(owns_BigLock_LL)(ptid));
    VG_TRACK ( pre_thread_ll_create, tid, tst->tid );
 }
 
diff --git a/coregrind/m_syswrap/syswrap-ppc32-linux.c b/coregrind/m_syswrap/syswrap-ppc32-linux.c
index efa272fb3e..715e685dd1 100644
--- a/coregrind/m_syswrap/syswrap-ppc32-linux.c
+++ b/coregrind/m_syswrap/syswrap-ppc32-linux.c
@@ -335,6 +335,7 @@ static SysRes do_clone ( ThreadId ptid,
       know that this thread has come into existence.  If the clone
       fails, we'll send out a ll_exit notification for it at the out:
       label below, to clean up. */
+   vg_assert(VG_(owns_BigLock_LL)(ptid));
    VG_TRACK ( pre_thread_ll_create, ptid, ctid );
 
    if (flags & VKI_CLONE_SETTLS) {
diff --git a/coregrind/m_syswrap/syswrap-ppc64-linux.c b/coregrind/m_syswrap/syswrap-ppc64-linux.c
index b55bee6728..75137f2f01 100644
--- a/coregrind/m_syswrap/syswrap-ppc64-linux.c
+++ b/coregrind/m_syswrap/syswrap-ppc64-linux.c
@@ -363,6 +363,7 @@ static SysRes do_clone ( ThreadId ptid,
       know that this thread has come into existence.  If the clone
       fails, we'll send out a ll_exit notification for it at the out:
       label below, to clean up. */
+   vg_assert(VG_(owns_BigLock_LL)(ptid));
    VG_TRACK ( pre_thread_ll_create, ptid, ctid );
 
    if (flags & VKI_CLONE_SETTLS) {
diff --git a/coregrind/m_syswrap/syswrap-s390x-linux.c b/coregrind/m_syswrap/syswrap-s390x-linux.c
index ae8b1a4dbd..15f8f23803 100644
--- a/coregrind/m_syswrap/syswrap-s390x-linux.c
+++ b/coregrind/m_syswrap/syswrap-s390x-linux.c
@@ -287,6 +287,7 @@ static SysRes do_clone ( ThreadId ptid,
       know that this thread has come into existence.  If the clone
       fails, we'll send out a ll_exit notification for it at the out:
       label below, to clean up. */
+   vg_assert(VG_(owns_BigLock_LL)(ptid));
    VG_TRACK ( pre_thread_ll_create, ptid, ctid );
 
    if (flags & VKI_CLONE_SETTLS) {
diff --git a/coregrind/m_syswrap/syswrap-x86-linux.c b/coregrind/m_syswrap/syswrap-x86-linux.c
index 2e64200866..a79bc45124 100644
--- a/coregrind/m_syswrap/syswrap-x86-linux.c
+++ b/coregrind/m_syswrap/syswrap-x86-linux.c
@@ -303,6 +303,7 @@ static SysRes do_clone ( ThreadId ptid,
       if we don't state the new thread exists prior to that point.
       If the clone fails, we'll send out a ll_exit notification for it
       at the out: label below, to clean up. */
+   vg_assert(VG_(owns_BigLock_LL)(ptid));
    VG_TRACK ( pre_thread_ll_create, ptid, ctid );
 
    if (flags & VKI_CLONE_SETTLS) {
diff --git a/coregrind/pub_core_scheduler.h b/coregrind/pub_core_scheduler.h
index 8d3d97c5ac..5e6042a324 100644
--- a/coregrind/pub_core_scheduler.h
+++ b/coregrind/pub_core_scheduler.h
@@ -78,6 +78,9 @@ extern void VG_(release_BigLock) ( ThreadId tid,
 /* Matching function to acquire_BigLock_LL. */
 extern void VG_(release_BigLock_LL) ( HChar* who );
 
+/* Whether the specified thread owns the big lock. */
+extern Bool VG_(owns_BigLock_LL) ( ThreadId tid );
+
 /* Yield the CPU for a while.  Drops/acquires the lock using the
    normal (non _LL) functions. */
 extern void VG_(vg_yield)(void);