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
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 0xa42e2c0c in __lll_lock_wait_private
(futex=futex@entry=0xa43869a0 ) at ./lowlevellock.c:33
#1 0xa426b6e8 in __GI___libc_malloc (bytes=bytes@entry=584) at
malloc.c:2888
#2 0xa425ace8 in __GI___open_memstream (bufloc=0x655b4670,
bufloc@entry=0x655b46d0, sizeloc=0x655b4678,
sizeloc@entry=0x655b46d8) at memstream.c:76
#3 0xa42cef18 in __GI___vsyslog_chk (ap=..., fmt=0xa4be2990 "%s",
flag=-1, pri=27) at ../misc/syslog.c:167
#4 __syslog (pri=pri@entry=27, fmt=fmt@entry=0xa4be2990 "%s") at
../misc/syslog.c:117
#5 0xa4bd7ab4 in unix_signal_handler (signum=,
si=, uc=) at
/home/gannega/vpp/build-data/../src/vlib/unix/main.c:119
#6
#7 0xa42654e0 in malloc_consolidate (av=av@entry=0xa43869a0
) at malloc.c:4182
#8 0xa4269354 in malloc_consolidate (av=0xa43869a0 )
at malloc.c:4151
#9 _int_malloc (av=av@entry=0xa43869a0 ,
bytes=bytes@entry=32816) at malloc.c:3450
#10 0xa426b5b4 in __GI___libc_malloc (bytes=bytes@entry=32816) at
malloc.c:2890
#11 0xa4299000 in __alloc_dir (statp=0x655b5d48, flags=0,
close_fd=true, fd=5) at ../sysdeps/posix/opendir.c:247
#12 opendir_tail (fd=) at ../sysdeps/posix/opendir.c:145
#13 __opendir (name=name@entry=0xa4bdf258 "/sys/bus/pci/devices") at
../sysdeps/posix/opendir.c:200
#14 0xa4bde088 in foreach_directory_file
(dir_name=dir_name@entry=0xa4bdf258 "/sys/bus/pci/devices",
f=f@entry=0xa4baf4a8 , arg=arg@entry=0xa4c0af30
,
scan_dirs=scan_dirs@entry=0) at
/home/gannega/vpp/build-data/../src/vlib/unix/util.c:59
#15 0xa4baed64 in linux_pci_init (vm=0xa4c0af30 )
at /home/gannega/vpp/build-data/../src/vlib/linux/pci.c:648
#16 0xa4bae504 in vlib_call_init_exit_functions (vm=0xa4c0af30
, head=, call_once=call_once@entry=1) at
/home/gannega/vpp/build-data/../src/vlib/init.c:57
#17 0xa4bae548 in vlib_call_all_init_functions (vm=) at
/home/gannega/vpp/build-data/../src/vlib/init.c:75
#18 0xa4bb3838 in vlib_main (vm=,
vm@entry=0xa4c0af30 , input=input@entry=0x655b5fc8)
at /home/gannega/vpp/build-data/../src/vlib/main.c:1748
#19 0xa4bd7c0c in thread0 (arg=281473445834544) at
/home/gannega/vpp/build-data/../src/vlib/unix/main.c:567
#20 0xa44f3e38 in clib_calljmp () at
/home/gannega/vpp/build-data/../src/vppinfra/longjmp.S:676
Best regards,
--
Gabriel Ganne
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