On Mon, 13 Jun 2022 14:48:45 +0500 Sarosh Arif <sarosh.a...@emumba.com> wrote:
> Thank you for help, I'll do it this way. > > On Sat, Jun 11, 2022 at 9:25 PM Mattias Rönnblom <hof...@lysator.liu.se> > wrote: > > > > On 2022-06-10 08:04, Sarosh Arif wrote: > > > On Thu, Jun 9, 2022 at 8:26 PM Stephen Hemminger > > > <step...@networkplumber.org> wrote: > > >> > > >> On Thu, 09 Jun 2022 12:47:43 +0000 > > >> bugzi...@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.a...@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. > > > > Is there anything except <rte_atomic.h> that is/should be async-signal-safe? > > > > >> 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? > > > > The standard solution is that the signal handler using some appropriate, > > async-signal-safe way talks to the main thread, which then goes on to > > cleanly terminate the application. > > > > A write() to an fd, or an atomic store to a flag are two options. Patch is pending (why is it not merged?) to describe what is signal safe. https://patchwork.dpdk.org/project/dpdk/patch/20220711230448.557715-1-step...@networkplumber.org/
