Date: Fri, 7 Dec 2018 16:51:03 -0600 From: "A. Wilcox" <awilfox@...lielinux.org> To: musl@...ts.openwall.com Subject: Re: aio_cancel segmentation fault for in progress write requests On 12/07/18 14:35, Markus Wichmann wrote: > On Fri, Dec 07, 2018 at 01:13:44PM -0600, A. Wilcox wrote: >> So, my best theory is that running inside a debugger (gdb, valgrind) >> makes it slow enough that it no longer races. > > Two ideas to investigate further. 1: Produce a coredump ("ulimit -c > unlimited"). That won't interfere with timing, but I have no clue if > coredumps work with multithreading. Core was generated by `./aioWrite '. Program terminated with signal SIGSEGV, Segmentation fault. #0 __cp_end () at src/thread/powerpc64/syscall_cp.s:32 32 src/thread/powerpc64/syscall_cp.s: No such file or directory. [Current thread is 1 (LWP 5507)] (gdb) bt #0 __cp_end () at src/thread/powerpc64/syscall_cp.s:32 #1 0x00003fffa768f2a4 in __syscall_cp_c (nr=180, u=512512, v=0, w=0, x=0, y=0, z=0) at src/thread/pthread_cancel.c:35 #2 0x00003fffa768e008 in __syscall_cp (nr=<optimized out>, u=<optimized out>, v=<optimized out>, w=<optimized out>, x=<optimized out>, y=<optimized out>, z=<optimized out>) at src/thread/__syscall_cp.c:20 #3 0x00003fffa76969f4 in pwrite (fd=<optimized out>, buf=<optimized out>, size=<optimized out>, ofs=<optimized out>) at src/unistd/pwrite.c:7 #4 0x00003fffa763eddc in io_thread_func (ctx=<optimized out>) at src/aio/aio.c:240 #5 0x00003fffa768f76c in start (p=0x3fffa76e8af8) at src/thread/pthread_create.c:147 #6 0x00003fffa769b608 in __clone () at src/thread/powerpc64/clone.s:43 (gdb) thread 2 [Switching to thread 2 (LWP 5506)] #0 0x00003fffa7637144 in __syscall4 (d=0, c=-1, b=128, a=512, n=221) at ./arch/powerpc64/syscall_arch.h:54 54 ./arch/powerpc64/syscall_arch.h: No such file or directory. (gdb) bt #0 0x00003fffa7637144 in __syscall4 (d=0, c=-1, b=128, a=512, n=221) at ./arch/powerpc64/syscall_arch.h:54 #1 __wait (addr=0x200, waiters=0x0, val=<optimized out>, priv=<optimized out>) at src/thread/__wait.c:13 #2 0x00003fffa763f07c in aio_cancel (fd=<optimized out>, cb=0x3fffffafd2b8) at src/aio/aio.c:356 #3 0x000000012034c044 in main () 221 is SYS_futex. Wow, that looks wrong. Best, --arw -- A. Wilcox (awilfox) Project Lead, Adélie Linux https://www.adelielinux.org Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)
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