System: Ubuntu 20.10 / Linux kernel 5.8.0-48-generic / x86_64 / KDE environment If you send the SIGUSR1 signal to a process using webkitgtk (WebKit2Gtk-4.0 version 2.30.6), the process segfaults. Here is a gdb log (the process is the Gambas interpreter): --------------------------------------------------------------------------------------------- GNU gdb (Ubuntu 9.2-0ubuntu2) 9.2 Copyright (C) 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from gbx3... Attaching to program: /usr/bin/gbx3, process 24324 [New LWP 24331] [New LWP 24332] [New LWP 24334] [New LWP 24335] [New LWP 24336] [New LWP 24337] [New LWP 24342] [New LWP 24345] [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". 0x00007f6b4f6ac66f in __GI___poll (fds=0x556d2627bc10, nfds=3, timeout=5853) at ../sysdeps/unix/sysv/linux/poll.c:29 29 ../sysdeps/unix/sysv/linux/poll.c: Aucun fichier ou dossier de ce type. (gdb) cont Continuing. [Thread 0x7f6b38bfb640 (LWP 24342) exited] Thread 1 "gbx3" received signal SIGUSR1, User defined signal 1. 0x00007f6b4f6ac66f in __GI___poll (fds=0x556d2627bc10, nfds=3, timeout=90000) at ../sysdeps/unix/sysv/linux/poll.c:29 29 in ../sysdeps/unix/sysv/linux/poll.c (gdb) cont Continuing. Thread 1 "gbx3" received signal SIGSEGV, Segmentation fault. WTF::Thread::signalHandlerSuspendResume () at ../Source/WTF/wtf/posix/ThreadingPOSIX.cpp:121 121 ../Source/WTF/wtf/posix/ThreadingPOSIX.cpp: Aucun fichier ou dossier de ce type. (gdb) bt #0 WTF::Thread::signalHandlerSuspendResume(int, siginfo_t*, void*) () at ../Source/WTF/wtf/posix/ThreadingPOSIX.cpp:121 #1 0x00007f6b4f5e0950 in <signal handler called> () at /lib/x86_64-linux-gnu/libc.so.6 #2 0x00007f6b4f6ac66f in __GI___poll (fds=0x556d2627bc10, nfds=3, timeout=90000) at ../sysdeps/unix/sysv/linux/poll.c:29 #3 0x00007f6b4bc0d86e in () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 #4 0x00007f6b4bc0d9a3 in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 #5 0x00007f6b4c25aaf5 in gtk_main_iteration_do (blocking=blocking@entry=1) at ../../../../gtk/gtkmain.c:1456 #6 0x00007f6b4d219cea in MAIN_do_iteration(bool) (do_not_block=do_not_block@entry=false) at main.cpp:689 #7 0x00007f6b4d219d3e in hook_loop() () at main.cpp:586 #8 0x0000556d24bd01d2 in main (argc=<optimized out>, argv=<optimized out>) at gbx.c:480 (gdb) disassemble Dump of assembler code for function WTF::Thread::signalHandlerSuspendResume(int, siginfo_t*, void*): 0x00007f6b43de2890 <+0>: endbr64 0x00007f6b43de2894 <+4>: push %rbp 0x00007f6b43de2895 <+5>: push %rbx 0x00007f6b43de2896 <+6>: sub $0x98,%rsp 0x00007f6b43de289d <+13>: mov %fs:0x28,%rax 0x00007f6b43de28a6 <+22>: mov %rax,0x88(%rsp) 0x00007f6b43de28ae <+30>: xor %eax,%eax 0x00007f6b43de28b0 <+32>: mov 0x3578c9(%rip),%rbx # 0x7f6b4413a180 <_ZN3WTFL12targetThreadE> => 0x00007f6b43de28b7 <+39>: mov 0x40(%rbx),%eax 0x00007f6b43de28ba <+42>: test %eax,%eax 0x00007f6b43de28bc <+44>: jne 0x7f6b43de2958 <WTF::Thread::signalHandlerSuspendResume(int, siginfo_t*, void*)+200> 0x00007f6b43de28c2 <+50>: mov %rsp,%rcx 0x00007f6b43de28c5 <+53>: mov 0x10(%rbx),%rax 0x00007f6b43de28c9 <+57>: cmp %rcx,%rax 0x00007f6b43de28cc <+60>: jb 0x7f6b43de28d9 <WTF::Thread::signalHandlerSuspendResume(int, siginfo_t*, void*)+73> 0x00007f6b43de28ce <+62>: test %rax,%rax 0x00007f6b43de28d1 <+65>: je 0x7f6b43de28d9 <WTF::Thread::signalHandlerSuspendResume(int, siginfo_t*, void*)+73> 0x00007f6b43de28d3 <+67>: cmp 0x18(%rbx),%rcx 0x00007f6b43de28d7 <+71>: ja 0x7f6b43de2910 <WTF::Thread::signalHandlerSuspendResume(int, siginfo_t*, void*)+128> 0x00007f6b43de28d9 <+73>: movq $0x0,0x38(%rbx) 0x00007f6b43de28e1 <+81>: mov 0x88(%rsp),%rax 0x00007f6b43de28e9 <+89>: sub %fs:0x28,%rax 0x00007f6b43de28f2 <+98>: jne 0x7f6b43de2975 <WTF::Thread::signalHandlerSuspendResume(int, siginfo_t*, void*)+229> ... (gdb) info registers rax 0x0 0 rbx 0x0 0 rcx 0x7f6b4f6ac66f 140098870625903 rdx 0x7ffc6646e500 140722024408320 rsi 0x7ffc6646e630 140722024408624 rdi 0xa 10 rbp 0x556d2627bc10 0x556d2627bc10 rsp 0x7ffc6646e450 0x7ffc6646e450 r8 0x0 0 r9 0x7f6b4bcea280 140098810061440 r10 0x7ffc664fd080 140722024992896 r11 0x293 659 r12 0x3 3 r13 0x7ffc6646eb04 140722024409860 r14 0x15f90 90000 r15 0x556d25e731c0 93927275704768 rip 0x7f6b43de28b7 0x7f6b43de28b7 <WTF::Thread::signalHandlerSuspendResume(int, siginfo_t*, void*)+39> eflags 0x10246 [ PF ZF IF RF ] cs 0x33 51 ss 0x2b 43 ds 0x0 0 es 0x0 0 fs 0x0 0 gs 0x0 0 ---------------------------------------------------------------------------------------------