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Wed, 21 Apr 2021 07:35:23 +0000 (GMT) Subject: Re: [PATCH v4 05/10] signal: Introduce TRAP_PERF si_code and si_perf to siginfo From: Marek Szyprowski To: Marco Elver Cc: Peter Zijlstra , Alexander Shishkin , Arnaldo Carvalho de Melo , Ingo Molnar , Jiri Olsa , Mark Rutland , Namhyung Kim , Thomas Gleixner , Alexander Potapenko , Al Viro , Arnd Bergmann , Christian Brauner , Dmitry Vyukov , Jann Horn , Jens Axboe , Matt Morehouse , Peter Collingbourne , Ian Rogers , Oleg Nesterov , kasan-dev , linux-arch , linux-fsdevel , LKML , the arch/x86 maintainers , "open list:KERNEL SELFTEST FRAMEWORK" , Geert Uytterhoeven , Bartlomiej Zolnierkiewicz Message-ID: Date: Wed, 21 Apr 2021 09:35:22 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: <43f8a3bf-34c5-0fc9-c335-7f92eaf23022@samsung.com> Content-Transfer-Encoding: 7bit Content-Language: en-US X-Brightmail-Tracker: H4sIAAAAAAAAA02Sf1DTZRzHe76/9mW59WViPKGH3TjlsAOCs3q0DrPr8uvZeXrdJe0qWPrl R/LDbS7MREEOGjtAGZY6FFaRcIBuTRgymeIo1o4xYRyhHor8CAUb3FKLqFF++V7Ff6/P53l/ ns/7/dxD4zILFUFn5uzn1DnKLDklJmzdf1yPdQweSX3R+Es80t+5RCGd9TSJgoZuEWq6fYxC 350yk6hwJgodHy0RoRJPG4kmbzkw9HnAgSNT8SMR8rlj0Q+9QQw1TI5gSGd/TKAOh5tAA/Yz FDo5PEuhb4f6MfTNtU4S+TpNGDp6rpVArVeLATo2PEQhV3knhi5av8DR9aCLRHOWcfL1VWxz TTNg/5w3ADZ4NoCzJquW7ah0U+zFhnXsQK+WtTaWUuyM1ytinV06wNa4d7KzVwYptqKlEbAP rZGsdcKP7XhGIX5tD5eV+Qmnjk9KFWfYH5tF+wLPHqgr9JEFoFWmBzQNmfXQdnmXHoTQMqYB wAffhwr8CMDAiErghwBeufE8z7y8rsVB6IH4Sb8ewBablxSKAIBGmx7jVcsZBezy9uE8U0wC 1Pv1FM9hjBz6xytwfgBnBmmoa+/CeBcSJgnWTW/lNQSzBtbqRhZnVzAfwZu+vxdZwoRC9+kJ gucQZhM8b6leZJxZDdv8Z3CBw+GtiVqMvx8yDjG8oG+nBNtvwlmbBxd4OZx2tYgEXgV7qsoI YaAIwFHveZFQlAE4cPQUEFSvwmHvPMU7xZkYaLbHC+3NcNpixIRnlMIb/lDBhBQabCdxoS2B uhKZoF4Lja4L/6291ufDjwO5cUk045I4xiVxjP/vNQGiEYRzWk12OqdJyOHy4jTKbI02Jz1u d262FTz51D0Lrl8vgbPTgTgnwGjgBJDG5WGSkfxDqTLJHuWnBzl1bopam8VpnGAlTcjDJY3V zSkyJl25n9vLcfs49b+nGB0SUYDFlN3TFm/vfvf3WOdYRFpUkssyNTbWbyi+vEnliWub8wdL PRvUivIJhWohrRzr21ihWvP17uqt9o5sc9T7D642sFkKQ9Mbwe3RJulm2+3D7pdD31MHKsNS 0yT5PxbFSV/am/ccmL154C4WPBTTmxh/sMBXuEWFP61ySTMTa+/137Unj29smvlqWdGH3oQj huCybXkxnE6x463IDlPrgm7ttrdH71cOVddUbdglVQ6l6NXGjM4TaOVfny3Q0Vni33qche84 B2elAVJW/zE5Wbrzqcj8OV1ybnR3Z45pYioEM5/rKR7ZEpZYn3zn5xXt65vJFzxTq39K+eDw /dKM1C9fma+SE5oMZcI6XK1R/gNsDtkAQwQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrKKsWRmVeSWpSXmKPExsVy+t/xe7p7rtYnGPw+bGPRdW8Hm0XHppms Fn8nHWO3WH23n81i44z1rBaN75QtJjxsY7doO7Od1eLZrb1MFu0f9zJbLGj9wm5x6aSuxdGz f5ksVjy7z2TRsesri8WevSdZLC7vmsNmMf3OezaLpdcvMlksPniA1eLSgQVMFk3LtrJYbN3f ymjRf+c6m8Xx3gNMFps3TWW2OP/3OKvFjw2PWR1kPNbMW8Po8fvXJEaPv3M/Mnss2FTqsWfi STaPzSu0PC6fLfXYtKqTzePduXPsHocOdzB6zDsZ6PF+31U2j74tqxg9Pm+S89j05C1TAH+U nk1RfmlJqkJGfnGJrVK0oYWRnqGlhZ6RiaWeobF5rJWRqZK+nU1Kak5mWWqRvl2CXsaur+vZ Cz6KVSxpvMTawLhVqIuRk0NCwERiyZa9LCC2kMBSRomXhwIh4jISJ6c1sELYwhJ/rnWxdTFy AdW8Z5R487CRHSQhLBAlcenvO2YQm03AUKLrLUgRJ4eIgJLE28d9zCANzAI3OSSW7HzCBNH9 ikli28qPQA4HB6+AncSSV54gDSwCqhLzO+6DDRIVSJK4d3klmM0rIChxcuYTsOs4Bewl1m6Y DWYzC5hJzNv8kBnClpfY/nYOlC0ucevJfKYJjEKzkLTPQtIyC0nLLCQtCxhZVjGKpJYW56bn FhvqFSfmFpfmpesl5+duYgSmp23Hfm7ewTjv1Ue9Q4xMHIyHGCU4mJVEeO/X1iQI8aYkVlal FuXHF5XmpBYfYjQF+mcis5Rocj4wQeaVxBuaGZgamphZGphamhkrifNunbsmXkggPbEkNTs1 tSC1CKaPiYNTqoFpR83eJUpa2Zkrth3UFmJvi0o89WLNjLY3149aqCsXrnqX+ohhquiGI0k7 2R7GfBdmTi1J1ZFNuiI1pY9D3PJ+xcmnIU0HmNIaWounLbfcNMVO4oaPcvaR/Wwv303z0qg+ HVEXatT8oGDho+MOij2Pykz4v8vOfPH+k0dtulO+puoMGeFTUup+Dr6lDpOUL53x2LTOPJ/3 UCt32onLnqqpGV5HHhqLZxlq/bnt+ElgepnG/Lvv/7SI260+zCN66vIRhYlvDrgrfNeen33i tU3Ng26eJ4aK77bMPnMjXJvL4cyr5YwGm7ySH99tuWnlxnRpkjjj2/aJ3YV6s/fIlb9+rnBv pbPS1/rr0wr2PwlTYinOSDTUYi4qTgQAWVBtBtgDAAA= X-CMS-MailID: 20210421073525eucas1p2de039236195308aa06fdee8b77fe01c7 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20210420212618eucas1p102b427d1af9c682217dfe093f3eac3e8 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20210420212618eucas1p102b427d1af9c682217dfe093f3eac3e8 References: <20210408103605.1676875-1-elver@google.com> <20210408103605.1676875-6-elver@google.com> <1fbf3429-42e5-0959-9a5c-91de80f02b6a@samsung.com> <43f8a3bf-34c5-0fc9-c335-7f92eaf23022@samsung.com> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 21.04.2021 08:21, Marek Szyprowski wrote: > On 21.04.2021 00:42, Marco Elver wrote: >> On Tue, 20 Apr 2021 at 23:26, Marek Szyprowski >> wrote: >>> On 08.04.2021 12:36, Marco Elver wrote: >>>> Introduces the TRAP_PERF si_code, and associated siginfo_t field >>>> si_perf. These will be used by the perf event subsystem to send >>>> signals >>>> (if requested) to the task where an event occurred. >>>> >>>> Acked-by: Geert Uytterhoeven # m68k >>>> Acked-by: Arnd Bergmann # asm-generic >>>> Signed-off-by: Marco Elver >>> This patch landed in linux-next as commit fb6cc127e0b6 ("signal: >>> Introduce TRAP_PERF si_code and si_perf to siginfo"). It causes >>> regression on my test systems (arm 32bit and 64bit). Most systems fails >>> to boot in the given time frame. I've observed that there is a timeout >>> waiting for udev to populate /dev and then also during the network >>> interfaces configuration. Reverting this commit, together with >>> 97ba62b27867 ("perf: Add support for SIGTRAP on perf events") to let it >>> compile, on top of next-20210420 fixes the issue. >> Thanks, this is weird for sure and nothing in particular stands out. >> >> I have questions: >> -- Can you please share your config? > > This happens with standard multi_v7_defconfig (arm) or just defconfig > for arm64. > >> -- Also, can you share how you run this? Can it be reproduced in qemu? > Nothing special. I just boot my test systems and see that they are > waiting lots of time during the udev populating /dev and network > interfaces configuration. I didn't try with qemu yet. >> -- How did you derive this patch to be at fault? Why not just >> 97ba62b27867, given you also need to revert it? > Well, I've just run my boot tests with automated 'git bisect' and that > was its result. It was a bit late in the evening, so I didn't analyze > it further, I've just posted a report about the issue I've found. It > looks that bisecting pointed to a wrong commit somehow. >> If you are unsure which patch exactly it is, can you try just >> reverting 97ba62b27867 and see what happens? > > Indeed, this is a real faulty commit. Initially I've decided to revert > it to let kernel compile (it uses some symbols introduced by this > commit). Reverting only it on top of linux-next 20210420 also fixes > the issue. I'm sorry for the noise in this thread. I hope we will find > what really causes the issue. This was a premature conclusion. It looks that during the test I've did while writing that reply, the modules were not deployed properly and a test board (RPi4) booted without modules. In that case the board booted fine and there was no udev timeout. After deploying kernel modules, the udev timeout is back. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland