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Merge pull request #17504 from mjstapp/fix_fpm_cancel_race

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zebra: avoid a race during FPM dplane plugin shutdown
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Donald Sharp 2024-11-26 08:32:54 -05:00 committed by GitHub
parent bd37658018 277784fe34
commit e8fdbbeb7b
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1 changed files with 34 additions and 0 deletions
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34
zebra/dplane_fpm_nl.c
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@ -68,6 +68,8 @@
static const char *prov_name = "dplane_fpm_nl";
static atomic_bool fpm_cleaning_up;
struct fpm_nl_ctx {
/* data plane connection. */
int socket;
@ -524,6 +526,16 @@ static void fpm_connect(struct event *t);
static void fpm_reconnect(struct fpm_nl_ctx *fnc)
{
bool cleaning_p = false;
/* This is being called in the FPM pthread: ensure we don't deadlock
* with similar code that may be run in the main pthread.
*/
if (!atomic_compare_exchange_strong_explicit(
&fpm_cleaning_up, &cleaning_p, true, memory_order_seq_cst,
memory_order_seq_cst))
return;
/* Cancel all zebra threads first. */
event_cancel_async(zrouter.master, &fnc->t_lspreset, NULL);
event_cancel_async(zrouter.master, &fnc->t_lspwalk, NULL);
@ -551,6 +563,12 @@ static void fpm_reconnect(struct fpm_nl_ctx *fnc)
EVENT_OFF(fnc->t_read);
EVENT_OFF(fnc->t_write);
/* Reset the barrier value */
cleaning_p = true;
atomic_compare_exchange_strong_explicit(
&fpm_cleaning_up, &cleaning_p, false, memory_order_seq_cst,
memory_order_seq_cst);
/* FPM is disabled, don't attempt to connect. */
if (fnc->disabled)
return;
@ -1624,6 +1642,16 @@ static int fpm_nl_start(struct zebra_dplane_provider *prov)
static int fpm_nl_finish_early(struct fpm_nl_ctx *fnc)
{
bool cleaning_p = false;
/* This is being called in the main pthread: ensure we don't deadlock
* with similar code that may be run in the FPM pthread.
*/
if (!atomic_compare_exchange_strong_explicit(
&fpm_cleaning_up, &cleaning_p, true, memory_order_seq_cst,
memory_order_seq_cst))
return 0;
/* Disable all events and close socket. */
EVENT_OFF(fnc->t_lspreset);
EVENT_OFF(fnc->t_lspwalk);
@ -1644,6 +1672,12 @@ static int fpm_nl_finish_early(struct fpm_nl_ctx *fnc)
fnc->socket = -1;
}
/* Reset the barrier value */
cleaning_p = true;
atomic_compare_exchange_strong_explicit(
&fpm_cleaning_up, &cleaning_p, false, memory_order_seq_cst,
memory_order_seq_cst);
return 0;
}