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SUNRPC: Remove BUG_ON call sites

PATCH Superseded Dominique Martinet 2 participants 3 messages Nov 2, 2024 – Nov 6, 2024 Stable branch

v1 of 2 Superseded Latest is v2 →

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PATCH 1/1 SUNRPC: Remove BUG_ON call sites

From: Chuck Lever <[email protected]>

[ Upstream commit 789ce196a31dd13276076762204bee87df893e53 ]

There is no need to take down the whole system for these assertions.

I'd rather not attempt a heroic save here, as some bug has occurred that has left the transport data structures in an unknown state. Just warn and then leak the left-over resources.

---
I've hit this BUG at home when restarting the nfs-server service and while that didn't bring the whole system down it did kill a thread with the nfsd_mutex lock held, making exportfs & other related commands all hang in unkillable state trying to grab the lock.

So this is purely selfish so that this won't happen again next time I upgrade :-)

I'd like to say I have any idea why the bug hit on that 6.6.42 (the sv_permsocks one did) and help with the underlying issue, but I honestly didn't do anything fancy and don't have anything interesting in logs (except the bug itself, happy to forward it if someone cares); would have been possible to debug this if I had a crash dump but it's not setup on this machine and just having this down to WARN if probably good enough...

Cheers,

 net/sunrpc/svc.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
net/sunrpc/svc.c +5 -4
index 029c49065016..b43dc8409b1f 100644
@@ -577,11 +577,12 @@ svc_destroy(struct kref *ref)
 	timer_shutdown_sync(&serv->sv_temptimer);
 
 	/*
-	 * The last user is gone and thus all sockets have to be destroyed to
-	 * the point. Check this.
+	 * Remaining transports at this point are not expected.
 	 */
-	BUG_ON(!list_empty(&serv->sv_permsocks));
-	BUG_ON(!list_empty(&serv->sv_tempsocks));
+	WARN_ONCE(!list_empty(&serv->sv_permsocks),
+		  "SVC: permsocks remain for %s\n", serv->sv_program->pg_name);
+	WARN_ONCE(!list_empty(&serv->sv_tempsocks),
+		  "SVC: tempsocks remain for %s\n", serv->sv_program->pg_name);
 
 	cache_clean_deferred(serv);
 
Signature · 1 line
2.46.1
#1 lore raw

Dominique Martinet wrote on Sat, Nov 02, 2024 at 03:52:03PM +0900:

Quoted 6 lines

From: Chuck Lever <[email protected]>

[ Upstream commit 789ce196a31dd13276076762204bee87df893e53 ]

There is no need to take down the whole system for these assertions.

Quoted 8 lines

I'd rather not attempt a heroic save here, as some bug has occurred that has left the transport data structures in an unknown state. Just warn and then leak the left-over resources.

grmbl, missing my signed-off, sorry:

hopefully didn't miss anything else..

Signature · 1 line
Dominique
maintainer
#2 lore raw
Quoted 16 lines · Dominique Martinet

Dominique Martinet wrote on Sat, Nov 02, 2024 at 03:52:03PM +0900:

Quoted 6 lines

From: Chuck Lever <[email protected]>

[ Upstream commit 789ce196a31dd13276076762204bee87df893e53 ]

There is no need to take down the whole system for these assertions.

Quoted 8 lines

I'd rather not attempt a heroic save here, as some bug has occurred that has left the transport data structures in an unknown state. Just warn and then leak the left-over resources.

Quoted 4 lines

grmbl, missing my signed-off, sorry:

hopefully didn't miss anything else..

Can you resend with this fixed up so we don't have to manually edit this?

thanks,

greg k-h