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

[Sarosh Arif <sarosh.arif@emumba.com>]

On Thu, Jun 9, 2022 at 8:26 PM Stephen Hemminger
<stephen@networkplumber.org> wrote:
>
> 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()
>
Oh, I did not know that. This should be mentioned in the documentation.
> but then again regular glibc is not either.
Memory allocated with glibc malloc() is freed by itself upon closing
the application. My application runs as a secondary process, and it
needs to use rte_malloc() specifically because the memory should be
shared between the two processes. If I don't free it upon closure it
would just be leaked. Is there any other solution for it?