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From: "mschulkind at gmail dot com" <sourceware-bugzilla@sources.redhat.com> To: glibc-bugs@sources.redhat.com Subject: [Bug linuxthreads/761] New: vm86 system call makes pthreads segfault Date: Thu, 24 Feb 2005 05:40:00 -0000 [thread overview] Message-ID: <20050224054039.761.mschulkind@gmail.com> (raw) I first saw this bug when trying to use the vm86 system call with pthreads. I worked around this by not using pthreads in the same application. The problem was that I think the vm86 system call would segfault on return whenever pthreads was explicitly compiled in, but I"m not sure exactly when the segfault occured. I strongly suspect this is closely related to the following bug report. Now I have re-encountered this bug in a slightly different way. Even though I don't use pthreads, it looks like glibc does, and I'm having a similar problem. This is on gentoo with what they call glibc-2.3.4.20041102, this DOES NOT happen with glibc-2.3.4.20040808-r1 so it seems like something recent started to cause this. After a single call to the vm86 system call, then next subsequent call to printf causes a segfault. Here is the backtrace: #0 0x405dfcc3 in _pthread_cleanup_push_defer (buffer=0xbfffedd4, routine=0, arg=0x0) at cancel.c:181 #1 0x40668b9e in _IO_vfprintf (s=0x407447c0, format=0x804e2a0 "debug> ", ap=0xbffff204 "\001") at vfprintf.c:1272 #2 0x406714e0 in printf (format=0x0) at printf.c:34 #3 0x08049229 in debug_image () at debugger.cpp:81 #4 0x08048f9e in main (argc=1, argv=0x0) at main.cpp:43 Frames 3 and 4 are my program. The exact line in _pthreads_cleanup_push_defer that it breaks on is: "buffer->__canceltype = THREAD_GETMEM(self, p_canceltype);" I'll try to debug this if I can, but I don't know how much I can figure out. I can't even see right now how the code execution goes from _IO_vfprintf to _pthreads_cleanup_push_defer. I hope this is enough information. Let me know if you want more. -- Summary: vm86 system call makes pthreads segfault Product: glibc Version: 2.3.4 Status: NEW Severity: normal Priority: P2 Component: linuxthreads AssignedTo: gotom at debian dot or dot jp ReportedBy: mschulkind at gmail dot com CC: glibc-bugs at sources dot redhat dot com GCC target triplet: i686-pc-linux-gnu http://sources.redhat.com/bugzilla/show_bug.cgi?id=761 ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is.
next reply other threads:[~2005-02-24 5:40 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2005-02-24 5:40 mschulkind at gmail dot com [this message] 2005-03-15 8:20 ` [Bug linuxthreads/761] " jakub at redhat dot com 2005-03-18 6:46 ` mschulkind at gmail dot com 2005-03-20 15:52 ` gotom at debian dot or dot jp
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