From: ch...@onthe.net.au
To: bug-bash@gnu.org
Subject: File descriptor leak
Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 -fdebug-prefix-map=/build/bash-2bxm7h/bash-5.0=.
-fstack-protector-strong -Wformat -Werror=format-security -Wall
-Wno-parentheses -Wno-format-security
uname output: Linux b2 5.7.9-otn-00003-g8c0bb49bc11c #1 SMP Fri Jul 17 04:37:20
UTC 2020 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.0
Patch Level: 3
Release Status: release
Description:
Bash is leaking a file descriptor.
Repeat-By:
----------------------------------------------------------------------
#!/bin/bash
if :
then
while read l
do
grep . /proc/$$/fdinfo/*
pvs > /dev/null
done < <( echo )
echo
fi
----------------------------------------------------------------------
The script generates output like:
/proc/2320431/fdinfo/0:pos: 0
/proc/2320431/fdinfo/0:flags: 0100000
/proc/2320431/fdinfo/0:mnt_id: 10
/proc/2320431/fdinfo/1:pos: 0
/proc/2320431/fdinfo/1:flags: 02
/proc/2320431/fdinfo/1:mnt_id: 20
/proc/2320431/fdinfo/10:pos: 0
/proc/2320431/fdinfo/10:flags: 02000002
/proc/2320431/fdinfo/10:mnt_id: 20
/proc/2320431/fdinfo/2:pos: 0
/proc/2320431/fdinfo/2:flags: 02
/proc/2320431/fdinfo/2:mnt_id: 20
/proc/2320431/fdinfo/255:pos: 123
/proc/2320431/fdinfo/255:flags: 02100000
/proc/2320431/fdinfo/255:mnt_id: 22
grep: /proc/2320431/fdinfo/3: No such file or directory
/proc/2320431/fdinfo/63:pos: 0
/proc/2320431/fdinfo/63:flags: 00
/proc/2320431/fdinfo/63:mnt_id: 10
File descriptor 63 (pipe:[189620647]) leaked on pvs invocation. Parent PID
2320431: /bin/bash
The last 'echo' within the 'if' is required to trigger the error.
The 'grep' is just to see the open file descriptors at that point, it's
not required to trigger the bug.
The 'pvs' (part of the lvm2 Logical Volume Manager suite) is also not
required to trigger the bug, it's just how I noticed the bug. The lvm2
stuff is particularly loud about file descriptor leaks.
Oh. Huh. I just noticed this also reproduces the problem:
----------------------------------------------------------------------
# pvs < <(echo) > /dev/null
File descriptor 63 (pipe:[190051752]) leaked on pvs invocation. Parent PID
204155: -bash
----------------------------------------------------------------------
This version of the problem may be subtly different because as previously
noted the first reproducer script requires the 'echo' within the 'if'.
See also:
- https://lists.gnu.org/archive/html/bug-bash/2017-01/msg00026.html
-
https://github.com/lvmteam/lvm2/blob/e10f20bc23088a2f9f7529f8f2b40d9c1fcb54c6/tools/lvmcmdline.c#L3333
--
Chris Dunlop
