[PATCH] Fix for uClibc linuxthreads stack checking
Robin Getz
rgetz at blackfin.uclinux.org
Thu Sep 15 11:36:57 UTC 2005
Bernd Schmidt found/fixed this problem in uClibc:
http://blackfin.uclinux.org/tracker/index.php?func=detail&aid=882&group_id=17&atid=141
Basically, the uClinux dist includes a few thread demos - thdm and bcdm -
running them simultaneously sometimes causes bus errors.
Bernd wrote:
>They occur in pthread_handle_sigrestart; thread_self returns a bogus value.
>I managed to capture a debugging log, it's attached as bad-log. If you
>look at it you'll notice that the initial stack bounds are bogus: bottom
>of stack is higher than top of stack. This appears to be because of a bug
>in NOMMU_INITIAL_THREAD_BOUNDS(tos,bos): if a new thread has a BOS equal
>to the initial thread's current TOS, it'll munge the initial thread's
>stack bounds. Fixed with the attached patch, which I've committed.
>This should fix the crashes people have seen, but since the bug was always
>hard to reproduce, I can't be 100% certain they are gone. Please retest,
>everyone...
This patch was made against our cvs, which has an older version of uClibc
in it - this code was recently moved from internals.h to descr.h in the
uclibc svn, but it still has the same problem:
http://www.uclibc.org/cgi-bin/viewcvs.cgi/trunk/uClibc/libpthread/linuxthreads/descr.h?rev=11408&view=auto
Comments welcome.
-robin
-------------- next part --------------
00057 : pthread_initialize: initial thread stack bounds: bos=0x1, tos=0x7920000
00057 : __pthread_initialize_manager: manager stack: size=8160, bos=0x7920000, tos=0x7921fe0
00057 : __pthread_initialize_manager: send REQ_DEBUG to manager thread
00057 : pthread_create: write REQ_CREATE to manager thread
00057 : pthread_create: before suspend(self)
00058 : __pthread_manager: before poll
00058 : __pthread_manager: after poll
00058 : __pthread_manager: before __libc_read
00058 : __pthread_manager: after __libc_read, n=148
00058 : __pthread_manager: got REQ_CREATE
00058 : pthread_allocate_stack: malloced chunk: base=0x7924000, size=0x4000
00058 : pthread_allocate_stack: thread stack: bos=0x7924000, tos=0x7927e20
00058 : pthread_allocate_stack: initial stack: bos=0x7921fe1, tos=0x7920000
00058 : pthread_handle_create: cloning new_thread = 0x7927e20
00058 : pthread_handle_create: new thread pid = 59
00058 : __pthread_manager: restarting 126957896
00057 : pthread_handle_sigrestart: 57
00058 : __pthread_manager: before poll
00059 : pthread_start_thread: pid 59
-------------- next part --------------
Index: internals.h
===================================================================
RCS file: /cvsroot/uclinux533/uClinux-dist/uClibc/libpthread/linuxthreads/internals.h,v
retrieving revision 1.2
diff -d -u -r1.2 internals.h
--- internals.h 18 Jul 2005 08:06:15 -0000 1.2
+++ internals.h 15 Sep 2005 10:53:12 -0000
@@ -259,7 +259,10 @@
extern char *__pthread_initial_thread_bos;
#ifndef __ARCH_HAS_MMU__
extern char *__pthread_initial_thread_tos;
-#define NOMMU_INITIAL_THREAD_BOUNDS(tos,bos) if ((tos)>=__pthread_initial_thread_bos && (bos)<=__pthread_initial_thread_tos) __pthread_initial_thread_bos = (tos)+1
+#define NOMMU_INITIAL_THREAD_BOUNDS(tos,bos) \
+ if ((tos)>=__pthread_initial_thread_bos \
+ && (bos)<__pthread_initial_thread_tos) \
+ __pthread_initial_thread_bos = (tos)+1
#else
#define NOMMU_INITIAL_THREAD_BOUNDS(tos,bos) /* empty */
#endif /* __ARCH_HAS_MMU__ */
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