Fix getpid in new threads after fork

Randolph,

Look familiar?

---------- Forwarded message ----------
From: Daniel Jacobowitz <[email protected]>
Date: Jul 31, 2006 12:15 PM
Subject: Fix getpid in new threads after fork
To: [email protected]

I noticed a failure with thread cancellation after fork, which turned out to be caused by the si_pid sanity check in sigcancel_handler. The PID was stale. This happened because the main program created a thread, joined it, and then forked. The cached thread was reused with a stale PID.

Patch and testcase attached. Tested on x86_64-pc-linux-gnu.

--
Daniel Jacobowitz
CodeSourcery

2006-07-31 Daniel Jacobowitz <[email protected]>

* Makefile (tests): Run tst-getpid3.
* allocatestack.c (__reclaim_stacks): Reset the PID on cached stacks.
* tst-getpid3.c: New test.

Index: nptl/Makefile
===================================================================
RCS file: /cvs/glibc/libc/nptl/Makefile,v
retrieving revision 1.180

diff -u -p -r1.180 Makefile
@@ -251,7 +251,7 @@ tests = tst-typesizes \
       tst-backtrace1 \
       tst-oddstacklimit \
       tst-vfork1 tst-vfork2 tst-vfork1x tst-vfork2x \
-       tst-getpid1 tst-getpid2 \
+       tst-getpid1 tst-getpid2 tst-getpid3 \
       tst-initializers1 $(patsubst %,tst-initializers1-%,c89 gnu89 c99 gnu99)

xtests = tst-setuid1 tst-setuid1-static

Index: nptl/allocatestack.c
===================================================================
RCS file: /cvs/glibc/libc/nptl/allocatestack.c,v
retrieving revision 1.62

diff -u -p -r1.62 allocatestack.c
@@ -758,6 +758,15 @@ __reclaim_stacks (void)
       }
    }
 
+  /* Reset the PIDs in any cached stacks.  */
+  list_for_each (runp, &stack_cache)
+    {
+      struct pthread *curp;
+
+      curp = list_entry (runp, struct pthread, list);
+      curp->pid = self->pid;
+    }
+
  /* Add the stack of all running threads to the cache.  */
  list_splice (&stack_used, &stack_cache);
 

Index: nptl/tst-getpid3.c
===================================================================
RCS file: nptl/tst-getpid3.c

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