Bug 1430038
| Summary: | Add missing hunk for upstream skbufhead-raw-lock RT patches | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Arnaldo Carvalho de Melo <acme> |
| Component: | kernel-rt | Assignee: | Arnaldo Carvalho de Melo <acme> |
| kernel-rt sub component: | Networking | QA Contact: | Jiri Kastner <jkastner> |
| Status: | CLOSED ERRATA | Docs Contact: | |
| Severity: | unspecified | ||
| Priority: | high | CC: | acme, bhu, jkacur, jkastner, jshortt, kzhang, lgoncalv, williams |
| Version: | 7.4 | ||
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2017-08-01 19:02:59 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | |||
| Bug Blocks: | 1353018, 1410158 | ||
Patch submitted and applied by Luis Claudio. Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2017:2077 Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2017:2077 |
Description of problem: The broken out patch tarball //www.kernel.org/pub/linux/kernel/projects/rt/4.8/patch-4.8.15-rt10.patch.xz comes with two patches: skbufhead-raw-lock.patch and skbufhead-raw-lock-free-skbs.patch, dealing with a patch management mishap by the 4.8.15-rt10 maintainer, that we have in our rhel-7.4/rt-master branch as just one patch, the original from 2011, by tglx: 85b9e707d00ab ("skbufhead-raw-lock.patch"). The problem is that something happened, a merge probably, and a hunk, the one that coincidentally is handled (slightly differently) in skbufhead-raw-lock-free-skbs.patch, disappeared, i.e. the freeing of the skbs moved to the softnet_data->tofree_q skb_queue_head list. So, to match 4.8.15-rt10 (and the original work by tglx), we need to apply skbufhead-raw-lock-free-skbs.patch. In a diff: diff -u rhel7/net/core/dev.c v4.8.15-rt10/net/core/dev.c @@ -4971,13 +5214,21 @@ struct softnet_data *sd = this_cpu_ptr(&softnet_data); unsigned long time_limit = jiffies + 2; int budget = netdev_budget; + struct sk_buff_head tofree_q; + struct sk_buff *skb; LIST_HEAD(list); LIST_HEAD(repoll); + __skb_queue_head_init(&tofree_q); + local_irq_disable(); + skb_queue_splice_init(&sd->tofree_queue, &tofree_q); list_splice_init(&sd->poll_list, &list); local_irq_enable(); + while ((skb = __skb_dequeue(&tofree_q))) + kfree_skb(skb); + for (;;) { struct napi_struct *n; ----- So the effect is that without this hunk skbs will get leaked when network devices are unregistered and packets remained in its queued to be processed.