Red Hat Bugzilla – Bug 131892
Last modified: 2007-11-30 17:10:48 EST
Description of problem:
file(1) very often segfaults.
Version-Release number of selected component (if applicable):
Easy to reproduce, but not predictable.
Steps to Reproduce:
while file /usr/share/texmf/omega/ocp/char2uni/inkoi8.ocp; do :; done
After about 100 runs or so:
Segmentation fault (core dumped)
I've verified that this happens on two separate machines.
I've used your test code, even did my own one with counter. Runs for
1000times without any segfault. May I have your kernel version? Can
you also check maximum open files on your system?
$ uname -r
$ ulimit -n
I've had confirmation on #fedora-devel that others can reproduce it.
Are you running on x86? Perhaps it's an arch-specific bug. I am
It isn't anything specific to that particular file; it happens with
all sorts of 'data' files. I see file(1) fail about 4 or 5 times at
the end of a tetex package build.
Here I've seen it fail with both 2.6.7-1.503 and 2.6.8-1.535, so I
don't think it's a kernel issue.
I'll get you a backtrace..
#0 0x00a7eef5 in file_softmagic (ms=0xa010830, buf=0xfeeca6c0 "",
#1 0x00a82c19 in file_buffer (ms=0xa010830, buf=0xfeeca6c0, nb=392)
#2 0x00a7b332 in magic_file (ms=0xa010830,
#3 0x08048d0c in process (
#4 0x080491b8 in main (argc=2, argv=0xfeedb874) at file.c:315
#5 0x00967a93 in __libc_start_main () from /lib/tls/libc.so.6
#6 0x08048b11 in _start ()
(gdb) info locals
ml = (struct mlist *) 0x110c8
(gdb) p *ml
Cannot access memory at address 0x110c8
Still fails when built with -O0, and having MALLOC_CHECK_=1 set does
not give any indication of memory problems.
It won't seem to fail when linked against efence.
valgrind didn't show any problems.
Compiling and running with mudflap (gcc35 -fmudflap -lmudflap) didn't
find any problems.
Good luck finding this one. :-)
Clarification: the only time that file(1) did *not* fail was when
linked against efence. Maybe that's useful information for tracking
$ while file /usr/share/texmf/omega/ocp/char2uni/inkoi8.ocp; do :;
selinux turned on in targetted mode..
[harald@jever ~]$ uname -r
[harald@jever ~]$ rpm -q glibc file
$ uname -m
I also have glibc-2.3.3-47 (i686).
echo 1 > /proc/sys/kernel/exec-shield-randomize
After doing this:
echo 1 > /proc/sys/kernel/print-fatal-signals
and re-running file until segfault, I get this from dmesg:
file/30580: potentially unexpected fatal signal 11.
code at 008f0ef5: 8b 52 0c 39 11 89 55 c4 0f 85 c9 fe ff ff 83 c4
Pid: 30580, comm: file
EIP: 0073:[<008f0ef5>] CPU: 0
EIP is at 0x8f0ef5
ESP: 007b:fef95a40 EFLAGS: 00210246 Not tainted (2.6.8-1.535)
EAX: 00000000 EBX: 008f72d8 ECX: 0a02e830 EDX: 0002f0c8
ESI: 00000001 EDI: f6de9500 EBP: fef95ac8 DS: 007b ES: 007b
CR0: 8005003b CR2: 0002f0d4 CR3: 003c0000 CR4: 000006d0
I can't seem to get it to fail under valgrind either. Presumably
valgrind and ElectricFence both bypass the exec-shield randomized base
address for the programs they examine.
Found and fixed this bug. 4.10-2.
Patch sent upstream.
*** Bug 140720 has been marked as a duplicate of this bug. ***