[Bug 1874824] Re: pgrep reports error "cannot allocate" when run without stack limit
Robie Basak
1874824 at bugs.launchpad.net
Wed Apr 7 12:47:09 UTC 2021
> The problem is the same for other popular tools like pkill from the
same package.
The SRU uploads fix pgrep, but not pkill. Isn't pkill also affected?
Rather than fixing that in a separate SRU causing users to have to
update twice, should we be fixing both at the same time? Or are you
intending to never fix pkill in an SRU? Are there any other commands
affected by the same issue?
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https://bugs.launchpad.net/bugs/1874824
Title:
pgrep reports error "cannot allocate" when run without stack limit
Status in procps package in Ubuntu:
Fix Released
Status in procps source package in Focal:
In Progress
Status in procps source package in Groovy:
In Progress
Status in procps source package in Hirsute:
Fix Released
Status in procps package in Debian:
New
Bug description:
[Impact]
- Users who have ulimit set high would see either slow
or failed pgrep and pkill commands
- Users who have ulimit set to unlimited would see
failed pgrep and pkill commands
- This bug occurs because the behavior of sysconf(_SC_ARG_MAX)
changed with a newer version of the kernel.
[Test Case]
- set the ulimit to unlimited by running `ulimit -S -s unlimited`
- run `pgrep bash` to see that the "cannot allocate" error is
printed and the command has failed.
[Where Problems Could Occur]
- We have set upper and lower limits on the size of the malloc, but
if further kernel versions break the call to sysconf in
unexpected ways we could still see problems.
[Original Description]
If you have no stack limit (ulimit -S -s unlimited), any pgrep call
will fail with an error:
> pgrep vim
pgrep: cannot allocate 4611686018427387903 bytes
If you have a high stack limit (e.g. ulimit -S -s 500000), pgrep is
very slow:
> time pgrep vim
2196
real 8.48s user 8.40s syst 0.07s busy 99% rmem 253444
The relevant upstream bug report could be: https://gitlab.com/procps-ng/procps/-/issues/152
Archlinux bug report: https://bugs.archlinux.org/task/66093
procps:
Installed: 2:3.3.16-1ubuntu2
500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages
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