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Re: The memory occupied by bash has been increasing due to the fork bomb
From: |
Chet Ramey |
Subject: |
Re: The memory occupied by bash has been increasing due to the fork bomb |
Date: |
Thu, 16 Mar 2023 15:40:39 -0400 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 |
On 3/11/23 6:41 AM, zju wrote:
The change was made in this pr:
https://git.savannah.gnu.org/cgit/bash.git/commit/?h=devel&id=ea31c00845c858098d232bd014bf27b5a63a668b
<https://git.savannah.gnu.org/cgit/bash.git/commit/?h=devel&id=ea31c00845c858098d232bd014bf27b5a63a668b>
The logic goes like this for interactive shells (non-interactive shells
don't ignore SIGTERM):
block SIGTERM in the parent
set the SIGTERM handler to SIG_DFL in the parent
fork, so the child, which still has SIGTERM blocked, has no pending signals
in the parent, restore the SIGTERM handler to SIG_IGN
if fork fails, abandon, reset the signal mask, and jump back to top level
- this is where other pipeline processes get sent SIGTERM
in the child, unblock SIGTERM -- if it received a SIGTERM after fork, it
will handle it now and exit due to the disposition being SIG_DFL
You might want to run a system call tracer and look at calls to kill and
sigaction.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU chet@case.edu http://tiswww.cwru.edu/~chet/
- Re: The memory occupied by bash has been increasing due to the fork bomb, (continued)