From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugeniy Paltsev Subject: Patch "asm-generic/bitops/lock.h: Rewrite using atomic_fetch_" causes kernel crash Date: Wed, 29 Aug 2018 18:33:53 +0000 Message-ID: <1535567633.4465.23.camel@synopsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Language: en-US Content-ID: Sender: linux-kernel-owner@vger.kernel.org To: "linux-kernel@vger.kernel.org" , "will.deacon@arm.com" Cc: "mingo@kernel.org" , "peterz@infradead.org" , "tglx@linutronix.de" , "linux-snps-arc@lists.infradead.org" , Alexey Brodkin , "yamada.masahiro@socionext.com" , "linux-arm-kernel@lists.infradead.org" , Vineet Gupta , "linux-arch@vger.kernel.org" List-Id: linux-arch.vger.kernel.org SGkgR3V5cywNClNpbmNlIHY0LjE5LXJjMSB3ZSBhcmUgZ2V0dGluZyBhIHNlcmlvdXMgcmVncmVz c2lvbiBvbiBwbGF0Zm9ybXMgd2l0aCBBUkMgYXJjaGl0ZWN0dXJlLg0KVGhlIGtlcm5lbCBoYXZl IGJlY29tZSB1bnN0YWJsZSBhbmQgc3BvbnRhbmVvdXNseSBjcmFzaGVzIG9uIExUUCB0ZXN0cyBl eGVjdXRpb24gLyBJTyB0ZXN0cyBvcg0KZXZlbiBvbiBib290Lg0KDQpJIGRvbid0IGtub3cgZXhh Y3RseSB3aGF0IGJyZWFrcyBidXQgYmlzZWN0IGNsZWFybHkgYXNzaWduIHRoZSBibGFtZSB0byB0 aGlzIGNvbW1pdDoNCjg0YzY1OTExMDNkYiAoImxvY2tpbmcvYXRvbWljcywgYXNtLWdlbmVyaWMv Yml0b3BzL2xvY2suaDogUmV3cml0ZSB1c2luZyBhdG9taWNfZmV0Y2hfKigpIikNCmh0dHBzOi8v Z2l0aHViLmNvbS90b3J2YWxkcy9saW51eC9jb21taXQvODRjNjU5MTEwM2RiZWFmMzkzYTA5MmEz ZmM3YjA5NTEwODI1ZjZiOQ0KDQpSZXZlcnRpbmcgdGhlIGNvbW1pdCBzb2x2ZXMgdGhpcyBwcm9i bGVtLg0KDQpJIHRlc3RlZCB2NC4xOS1yYzEgb24gQVJNICh3YW5kYm9hcmQsIGkubXg2LCAzMmJp dCwgcXVhcmQgY29yZSwgQVJNdjcpIHdoaWNoIHVzZXMgc2FtZQ0KZ2VuZXJpYyBiaXRvcHMgaW1w bGVtZW50YXRpb24gYW5kIGl0IHdvcmtzIGZpbmUuDQoNCkRvIHlvdSBoYXZlIGFueSBpZGVhcyB3 aGF0IHdlbnQgd3Jvbmc/DQotLSANCiBFdWdlbml5IFBhbHRzZXY= From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugeniy.Paltsev@synopsys.com (Eugeniy Paltsev) Date: Wed, 29 Aug 2018 18:33:53 +0000 Subject: Patch "asm-generic/bitops/lock.h: Rewrite using atomic_fetch_" causes kernel crash List-ID: Message-ID: <1535567633.4465.23.camel@synopsys.com> To: linux-snps-arc@lists.infradead.org Hi Guys, Since v4.19-rc1 we are getting a serious regression on platforms with ARC architecture. The kernel have become unstable and spontaneously crashes on LTP tests execution / IO tests or even on boot. I don't know exactly what breaks but bisect clearly assign the blame to this commit: 84c6591103db ("locking/atomics, asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*()") https://github.com/torvalds/linux/commit/84c6591103dbeaf393a092a3fc7b09510825f6b9 Reverting the commit solves this problem. I tested v4.19-rc1 on ARM (wandboard, i.mx6, 32bit, quard core, ARMv7) which uses same generic bitops implementation and it works fine. Do you have any ideas what went wrong? -- Eugeniy Paltsev From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugeniy.Paltsev@synopsys.com (Eugeniy Paltsev) Date: Wed, 29 Aug 2018 18:33:53 +0000 Subject: Patch "asm-generic/bitops/lock.h: Rewrite using atomic_fetch_" causes kernel crash Message-ID: <1535567633.4465.23.camel@synopsys.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Guys, Since v4.19-rc1 we are getting a serious regression on platforms with ARC architecture. The kernel have become unstable and spontaneously crashes on LTP tests execution / IO tests or even on boot. I don't know exactly what breaks but bisect clearly assign the blame to this commit: 84c6591103db ("locking/atomics, asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*()") https://github.com/torvalds/linux/commit/84c6591103dbeaf393a092a3fc7b09510825f6b9 Reverting the commit solves this problem. I tested v4.19-rc1 on ARM (wandboard, i.mx6, 32bit, quard core, ARMv7) which uses same generic bitops implementation and it works fine. Do you have any ideas what went wrong? -- Eugeniy Paltsev