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charset="utf-8" Content-Transfer-Encoding: base64 Sender: "ath11k" Errors-To: ath11k-bounces+ath11k=archiver.kernel.org@lists.infradead.org T24gVHVlLCBKdWwgMjYsIDIwMjIgYXQgMDg6NTM6NThQTSArMDMwMCwgS2FsbGUgVmFsbyB3cm90 ZToKPiBNYW5pdmFubmFuIFNhZGhhc2l2YW0gPG1hbmlAa2VybmVsLm9yZz4gd3JpdGVzOgo+IAo+ ID4gK2F0aDExaywgS2FsbGUKPiA+Cj4gPiBPbiBGcmksIEp1bCAyMiwgMjAyMiBhdCAxMToxNzox OEFNICswODAwLCBRaWFuZyBZdSB3cm90ZToKPiA+PiBUaGUgaXJxIGhhbmRsZXIgZm9yIGEgc2hh cmVkIElSUSBvdWdodCB0byBiZSBwcmVwYXJlZCBmb3IgcnVubmluZwo+ID4+IGV2ZW4gbm93IGl0 J3MgYmVpbmcgZnJlZWQuIFNvIGxldCdzIGNoZWNrIHRoZSBwb2ludGVyIHVzZWQgYnkKPiA+PiBt aGlfaXJxX2hhbmRsZXIgdG8gYXZvaWQgbnVsbCBwb2ludGVyIGFjY2VzcyBzaW5jZSBpdCBpcyBw cm9iYWJseQo+ID4+IHJlbGVhc2VkIGJlZm9yZSBmcmVlaW5nIElSUS4KPiA+PiAKPiA+PiBTaWdu ZWQtb2ZmLWJ5OiBRaWFuZyBZdSA8cXVpY19xaWFueXVAcXVpY2luYy5jb20+Cj4gPgo+ID4gUmV2 aWV3ZWQtYnk6IE1hbml2YW5uYW4gU2FkaGFzaXZhbSA8bWFuaUBrZXJuZWwub3JnPgo+IAo+IFRo aXMgZml4ZXMgdGhlIGNyYXNoIGFuZCBteSByZWdyZXNzaW9uIHRlc3RzIHBhc3Mgbm93LCB0aGFu a3MuIEJ1dAo+IHBsZWFzZSBzZWUgbXkgcXVlc3Rpb24gYmVsb3cuCj4gCj4gVGVzdGVkLWJ5OiBL YWxsZSBWYWxvIDxrdmFsb0BrZXJuZWwub3JnPgo+IAoKVGhhbmtzIEthbGxlIQoKPiA+PiArCS8q Cj4gPj4gKwkgKiBJZiBDT05GSUdfREVCVUdfU0hJUlEgaXMgc2V0LCB0aGUgSVJRIGhhbmRsZXIg d2lsbCBnZXQgaW52b2tlZCBkdXJpbmcgX19mcmVlX2lycSgpCj4gPj4gKwkgKiBhbmQgYnkgdGhh dCB0aW1lIG1oaV9jdHh0KCkgd291bGQndmUgZnJlZWQuIFNvIGNoZWNrIGZvciB0aGUgZXhpc3Rl bmNlIG9mIG1oaV9jdHh0Cj4gPj4gKwkgKiBiZWZvcmUgaGFuZGxpbmcgdGhlIElSUXMuCj4gPj4g KwkgKi8KPiA+PiArCWlmICghbWhpX2NudHJsLT5taGlfY3R4dCkgewo+ID4+ICsJCWRldl9kYmco Jm1oaV9jbnRybC0+bWhpX2Rldi0+ZGV2LAo+ID4+ICsJCQkibWhpX2N0eHQgaGFzIGJlZW4gZnJl ZWRcbiIpOwo+ID4+ICsJCXJldHVybiBJUlFfSEFORExFRDsKPiA+PiArCX0KPiAKPiBJIGRvbid0 IHNlZSBhbnkgcHJvdGVjdGlvbiBhY2Nlc3NpbmcgbWhpX2NudHJsLT5taGlfY3R4dCwgaXMgdGhp cyByZWFsbHkKPiBmcmVlIG9mIHJhY2UgY29uZGl0aW9ucz8KPiAKCkFzIFFpYW5nIHNhaWQsIGl0 IGlzIHNhZmUgdG8gYWNjZXNzIG1oaV9jdHh0IGhlcmUuCgpUaGFua3MsCk1hbmkKCj4gLS0gCj4g aHR0cHM6Ly9wYXRjaHdvcmsua2VybmVsLm9yZy9wcm9qZWN0L2xpbnV4LXdpcmVsZXNzL2xpc3Qv Cj4gCj4gaHR0cHM6Ly93aXJlbGVzcy53aWtpLmtlcm5lbC5vcmcvZW4vZGV2ZWxvcGVycy9kb2N1 bWVudGF0aW9uL3N1Ym1pdHRpbmdwYXRjaGVzCgotLSAK4K6u4K6j4K6/4K614K6j4K+N4K6j4K6p 4K+NIOCumuCupOCuvuCumuCuv+CuteCuruCvjQoKLS0gCmF0aDExayBtYWlsaW5nIGxpc3QKYXRo MTFrQGxpc3RzLmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1h bi9saXN0aW5mby9hdGgxMWsK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8305CC00144 for ; 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d=kernel.org; s=k20201202; t=1659104549; bh=FYp7dxRuDa2TzbtLpfE1k1l6o7hR4ycZLxQgQwCsplA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gI52e6Jn7VE10U5yCiJqdCtJ8vq4VD1COs74rMHOXEDNUAB313zvt0660JPDJ89vL uRPByAcorrzRsXtzw4UHnEJYFgnZ0epF0+cuXPtDnI7WiYrbh8tDpLbH5ehEusMPBg eNhTd/WKCWFGW0aqvwRSSQZedj1nbkhf51FcitmIv3mV+5IihAseMfE30NzpLOZ+yz Vbrkd030U5POnTAx7Z0DMhjniNQpxIMtQyv4s34uHp67VcwJhg0wPbvzzST6nu9tlq e55lT7qkLZFj0rAWah49KRFUemdcWzLi8jfIAxIEaMFW92wBqgfG7GfQR8uG/sz0BC dVxKcR7Sz1vGw== Date: Fri, 29 Jul 2022 19:52:21 +0530 From: Manivannan Sadhasivam To: Kalle Valo Cc: Qiang Yu , quic_hemantk@quicinc.com, loic.poulain@linaro.org, quic_jhugo@quicinc.com, mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, quic_cang@quicinc.com, ath11k@lists.infradead.org Subject: Re: [PATCH v3 1/1] bus: mhi: host: Fix up null pointer access in mhi_irq_handler Message-ID: <20220729142221.GA9937@thinkpad> References: <1658459838-30802-1-git-send-email-quic_qianyu@quicinc.com> <20220726080636.GE5522@workstation> <87czdrrc95.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87czdrrc95.fsf@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Tue, Jul 26, 2022 at 08:53:58PM +0300, Kalle Valo wrote: > Manivannan Sadhasivam writes: > > > +ath11k, Kalle > > > > On Fri, Jul 22, 2022 at 11:17:18AM +0800, Qiang Yu wrote: > >> The irq handler for a shared IRQ ought to be prepared for running > >> even now it's being freed. So let's check the pointer used by > >> mhi_irq_handler to avoid null pointer access since it is probably > >> released before freeing IRQ. > >> > >> Signed-off-by: Qiang Yu > > > > Reviewed-by: Manivannan Sadhasivam > > This fixes the crash and my regression tests pass now, thanks. But > please see my question below. > > Tested-by: Kalle Valo > Thanks Kalle! > >> + /* > >> + * If CONFIG_DEBUG_SHIRQ is set, the IRQ handler will get invoked during __free_irq() > >> + * and by that time mhi_ctxt() would've freed. So check for the existence of mhi_ctxt > >> + * before handling the IRQs. > >> + */ > >> + if (!mhi_cntrl->mhi_ctxt) { > >> + dev_dbg(&mhi_cntrl->mhi_dev->dev, > >> + "mhi_ctxt has been freed\n"); > >> + return IRQ_HANDLED; > >> + } > > I don't see any protection accessing mhi_cntrl->mhi_ctxt, is this really > free of race conditions? > As Qiang said, it is safe to access mhi_ctxt here. Thanks, Mani > -- > https://patchwork.kernel.org/project/linux-wireless/list/ > > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches -- மணிவண்ணன் சதாசிவம்