Hello, I'm hitting a crash with the following backtrace:
#0 0x0000000000000000 in ?? () #1 0x00000000004660dd in __error_internal (status=1, errnum=1073741826, message=0x9adcef1c, args=0x9adcef18, args@entry=0x156aa48, mode_flags=2598170400, mode_flags@entry=0) at error.c:243 #2 0x00000000004661d5 in __error (status=status@entry=0, errnum=<optimized out>, message=<optimized out>) at error.c:274 #3 0x0000000000401497 in error (__format=<optimized out>, __errnum=<optimized out>, __status=<optimized out>) at error.h:42 Note that PC is 0 in the top frame. Here's the relevant listing and backtrace of the frame #1: (gdb) l 238 { 239 #if defined _LIBC 240 /* We do not want this call to be cut short by a thread 241 cancellation. Therefore disable cancellation for now. */ 242 int state = PTHREAD_CANCEL_ENABLE; 243 __pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state); 244 #endif 245 246 flush_stdout (); 247 #ifdef _LIBC (gdb) disas Dump of assembler code for function __error_internal: 0x00000000004660b0 <+0>: push %r14 0x00000000004660b2 <+2>: mov %r8d,%r14d 0x00000000004660b5 <+5>: push %r13 0x00000000004660b7 <+7>: mov %rcx,%r13 0x00000000004660ba <+10>: push %r12 0x00000000004660bc <+12>: mov %rdx,%r12 0x00000000004660bf <+15>: push %rbp 0x00000000004660c0 <+16>: mov %esi,%ebp 0x00000000004660c2 <+18>: push %rbx 0x00000000004660c3 <+19>: mov %edi,%ebx 0x00000000004660c5 <+21>: xor %edi,%edi 0x00000000004660c7 <+23>: sub $0x10,%rsp 0x00000000004660cb <+27>: lea 0xc(%rsp),%rsi 0x00000000004660d0 <+32>: movl $0x1,0xc(%rsp) 0x00000000004660d8 <+40>: call 0x0 => 0x00000000004660dd <+45>: mov $0x569b10,%rax 0x00000000004660e4 <+52>: mov (%rax),%rdi 0x00000000004660e7 <+55>: call 0x433900 <_IO_fflush> "call 0x0", ouch! Clearly __pthread_setcancelstate has been pragma weak'd, and used here without a check. This is a statically linked x86_64-gnu (so, Hurd and HTL) executable. Commit 93d78ec1cba68184931b75bef29afd3aed30f43a "nptl: Move pthread_setcancelstate into libc" seems to be the culprit: that commit only moved the NPTL symbol into libc, yet changed the original __libc_ptf_call (__pthread_setcancelstate) calls to direct __pthread_setcancelstate calls, in this and many other places. This likely hasn't been noticed in the past because the only statically linked executables typically used on Hurd systems are the few bootstrap servers, and they're (presumably) all multithreaded. What would be the best way to get this fixed? (other than eventually moving htl into libc) Are the other pthread symbols also used unconditionally? Is there, or should there be, a test for this? Sergey