Re: [Bug 1030] rte_malloc() and rte_free() get stuck when used with signal handler

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu, 09 Jun 2022 12:47:43 +0000
bugzilla@dpdk.org wrote:

> https://bugs.dpdk.org/show_bug.cgi?id=1030
> 
>             Bug ID: 1030
>            Summary: rte_malloc() and rte_free() get stuck when used with
>                     signal handler
>            Product: DPDK
>            Version: 22.03
>           Hardware: All
>                 OS: Linux
>             Status: UNCONFIRMED
>           Severity: normal
>           Priority: Normal
>          Component: core
>           Assignee: dev@dpdk.org
>           Reporter: sarosh.arif@emumba.com
>   Target Milestone: ---
> 
> Created attachment 205
>   --> https://bugs.dpdk.org/attachment.cgi?id=205&action=edit  
> calls rte_malloc and rte_free in the handler and main code
> 
> I have a dpdk based application which uses rte_malloc() and rte_free()
> frequently in it's main code. The general method to close the application is
> though sending SIGINT. The application has a signal handler written for cleanup
> purposes before closing the application. The handler also uses rte_free() to
> release some of the memory during cleanup. The application gets stuck in a
> deadlock.
> 
> 
> Upon investigation I found out that both rte_free() and rte_malloc() use
> rte_spinlock_lock() function to place a lock on heap. While this lock is placed
> and the application receives SIGINT, it goes into the handler without releasing
> the lock. Since the handler itself calls rte_free() which tries to acquire the
> lock it gets stuck. 
> 
> 
> I have attached a sample application to reproduce this problem.
> 
> 
> Steps to reproduce this problem: 
> 
> 1. compile the code provided in attachment with any version of dpdk 
> 2. run the compiled binary
> 3. press ctrl+c till the prints stop 
> 
> Actual Results: 
> The application gets stuck in either rte_free() or rte_malloc()
> 
> Expected Results: 
> Application should allocate and free the memory without getting stuck
> 

rte_malloc and rte_free are not async sigsafe()

but then again regular glibc is not either.