In almost all cases, the glibc malloc heap will not be pickled since it's not used on a regular basis.
For some effort, one could replace the syslog library code, I guess. Thanks... Dave From: vpp-dev-boun...@lists.fd.io [mailto:vpp-dev-boun...@lists.fd.io] On Behalf Of Gabriel Ganne Sent: Tuesday, October 17, 2017 4:18 AM To: vpp-dev <vpp-dev@lists.fd.io> Subject: [vpp-dev] vpp deadlock - syslog in signal handler Hi, I have encountered a deadlock in vpp on the raising of a memory alloc exception. The signal is caught by unix_signal_handler(), which determines this is a fatal error and then syslogs the error message. The problem is that syslog() then tries to allocate a scratchpad memory, and deadlocks since allocation is the reason why I'm here in the first place. clib_warning() functions should be safe because all the memory needed is alloc'ed at init, but I don't see how this syslog() call can succeed. Should I just remove it ? Or is there a way I don't know about to still make this work ? Below is a backtrace of the problem: #0 0x0000ffffa42e2c0c in __lll_lock_wait_private (futex=futex@entry=0xffffa43869a0 <main_arena>) at ./lowlevellock.c:33 #1 0x0000ffffa426b6e8 in __GI___libc_malloc (bytes=bytes@entry=584) at malloc.c:2888 #2 0x0000ffffa425ace8 in __GI___open_memstream (bufloc=0xffff655b4670, bufloc@entry=0xffff655b46d0, sizeloc=0xffff655b4678, sizeloc@entry=0xffff655b46d8) at memstream.c:76 #3 0x0000ffffa42cef18 in __GI___vsyslog_chk (ap=..., fmt=0xffffa4be2990 "%s", flag=-1, pri=27) at ../misc/syslog.c:167 #4 __syslog (pri=pri@entry=27, fmt=fmt@entry=0xffffa4be2990 "%s") at ../misc/syslog.c:117 #5 0x0000ffffa4bd7ab4 in unix_signal_handler (signum=<optimized out>, si=<optimized out>, uc=<optimized out>) at /home/gannega/vpp/build-data/../src/vlib/unix/main.c:119 #6 <signal handler called> #7 0x0000ffffa42654e0 in malloc_consolidate (av=av@entry=0xffffa43869a0 <main_arena>) at malloc.c:4182 #8 0x0000ffffa4269354 in malloc_consolidate (av=0xffffa43869a0 <main_arena>) at malloc.c:4151 #9 _int_malloc (av=av@entry=0xffffa43869a0 <main_arena>, bytes=bytes@entry=32816) at malloc.c:3450 #10 0x0000ffffa426b5b4 in __GI___libc_malloc (bytes=bytes@entry=32816) at malloc.c:2890 #11 0x0000ffffa4299000 in __alloc_dir (statp=0xffff655b5d48, flags=0, close_fd=true, fd=5) at ../sysdeps/posix/opendir.c:247 #12 opendir_tail (fd=<optimized out>) at ../sysdeps/posix/opendir.c:145 #13 __opendir (name=name@entry=0xffffa4bdf258 "/sys/bus/pci/devices") at ../sysdeps/posix/opendir.c:200 #14 0x0000ffffa4bde088 in foreach_directory_file (dir_name=dir_name@entry=0xffffa4bdf258 "/sys/bus/pci/devices", f=f@entry=0xffffa4baf4a8 <scan_device>, arg=arg@entry=0xffffa4c0af30 <vlib_global_main>, scan_dirs=scan_dirs@entry=0) at /home/gannega/vpp/build-data/../src/vlib/unix/util.c:59 #15 0x0000ffffa4baed64 in linux_pci_init (vm=0xffffa4c0af30 <vlib_global_main>) at /home/gannega/vpp/build-data/../src/vlib/linux/pci.c:648 #16 0x0000ffffa4bae504 in vlib_call_init_exit_functions (vm=0xffffa4c0af30 <vlib_global_main>, head=<optimized out>, call_once=call_once@entry=1) at /home/gannega/vpp/build-data/../src/vlib/init.c:57 #17 0x0000ffffa4bae548 in vlib_call_all_init_functions (vm=<optimized out>) at /home/gannega/vpp/build-data/../src/vlib/init.c:75 #18 0x0000ffffa4bb3838 in vlib_main (vm=<optimized out>, vm@entry=0xffffa4c0af30 <vlib_global_main>, input=input@entry=0xffff655b5fc8) at /home/gannega/vpp/build-data/../src/vlib/main.c:1748 #19 0x0000ffffa4bd7c0c in thread0 (arg=281473445834544) at /home/gannega/vpp/build-data/../src/vlib/unix/main.c:567 #20 0x0000ffffa44f3e38 in clib_calljmp () at /home/gannega/vpp/build-data/../src/vppinfra/longjmp.S:676 Best regards, -- Gabriel Ganne
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