Messages in this thread |  | | From | Haiyang Zhang <> | Subject | RE: [PATCH net, 2/2] net: mana: Fix accessing freed irq affinity_hint | Date | Sun, 29 Jan 2023 18:51:17 +0000 |
| |
> -----Original Message----- > From: Michael Kelley (LINUX) <mikelley@microsoft.com> > Sent: Sunday, January 29, 2023 9:27 AM > To: Haiyang Zhang <haiyangz@microsoft.com>; linux-hyperv@vger.kernel.org; > netdev@vger.kernel.org > Cc: Haiyang Zhang <haiyangz@microsoft.com>; Dexuan Cui > <decui@microsoft.com>; KY Srinivasan <kys@microsoft.com>; Paul Rosswurm > <paulros@microsoft.com>; olaf@aepfle.de; vkuznets@redhat.com; > davem@davemloft.net; linux-kernel@vger.kernel.org; stable@vger.kernel.org > Subject: RE: [PATCH net, 2/2] net: mana: Fix accessing freed irq affinity_hint > > From: LKML haiyangz <lkmlhyz@microsoft.com> On Behalf Of Haiyang Zhang > Sent: Thursday, January 26, 2023 1:05 PM > > > > After calling irq_set_affinity_and_hint(), the cpumask pointer is > > saved in desc->affinity_hint, and will be used later when reading > > /proc/irq/<num>/affinity_hint. So the cpumask variable needs to be > > allocated per irq, and available until freeing the irq. Otherwise, > > we are accessing freed memory when reading the affinity_hint file. > > > > To fix the bug, allocate the cpumask per irq, and free it just > > before freeing the irq. > > Since the cpumask being passed to irq_set_affinity_and_hint() > always contains exactly one CPU, the code can be considerably > simplified by using the pre-calculated and persistent masks > available as cpumask_of(cpu). All allocation of cpumasks in this > code goes away, and you can set the affinity_hint to NULL in the > cleanup and remove paths without having to free any masks. > Great idea! Will update the patch accordingly.
- Haiyang
|  |