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Thu, 18 Apr 2024 21:29:59 +0200 Message-ID: Date: Thu, 18 Apr 2024 21:29:57 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [bug-report] task info hung problem in fb_deferred_io_work() To: Takashi Iwai , Nam Cao , Thomas Zimmermann Cc: Harshit Mogalapalli , Daniel Vetter , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, bigeasy@linutronix.de, patrik.r.jakobsson@gmail.com, LKML , Vegard Nossum , George Kennedy , Darren Kenny , chuansheng.liu@intel.com References: <271372d6-e665-4e7f-b088-dee5f4ab341a@oracle.com> <20240418160652.68df1a86@namcao> <87ttjywxv5.wl-tiwai@suse.de> Content-Language: en-US From: Helge Deller Autocrypt: addr=deller@gmx.de; keydata= xsFNBF3Ia3MBEAD3nmWzMgQByYAWnb9cNqspnkb2GLVKzhoH2QD4eRpyDLA/3smlClbeKkWT HLnjgkbPFDmcmCz5V0Wv1mKYRClAHPCIBIJgyICqqUZo2qGmKstUx3pFAiztlXBANpRECgwJ r+8w6mkccOM9GhoPU0vMaD/UVJcJQzvrxVHO8EHS36aUkjKd6cOpdVbCt3qx8cEhCmaFEO6u CL+k5AZQoABbFQEBocZE1/lSYzaHkcHrjn4cQjc3CffXnUVYwlo8EYOtAHgMDC39s9a7S90L 69l6G73lYBD/Br5lnDPlG6dKfGFZZpQ1h8/x+Qz366Ojfq9MuuRJg7ZQpe6foiOtqwKym/zV dVvSdOOc5sHSpfwu5+BVAAyBd6hw4NddlAQUjHSRs3zJ9OfrEx2d3mIfXZ7+pMhZ7qX0Axlq Lq+B5cfLpzkPAgKn11tfXFxP+hcPHIts0bnDz4EEp+HraW+oRCH2m57Y9zhcJTOJaLw4YpTY GRUlF076vZ2Hz/xMEvIJddRGId7UXZgH9a32NDf+BUjWEZvFt1wFSW1r7zb7oGCwZMy2LI/G aHQv/N0NeFMd28z+deyxd0k1CGefHJuJcOJDVtcE1rGQ43aDhWSpXvXKDj42vFD2We6uIo9D 1VNre2+uAxFzqqf026H6cH8hin9Vnx7p3uq3Dka/Y/qmRFnKVQARAQABzRxIZWxnZSBEZWxs ZXIgPGRlbGxlckBnbXguZGU+wsGRBBMBCAA7AhsDBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheA FiEERUSCKCzZENvvPSX4Pl89BKeiRgMFAl3J1zsCGQEACgkQPl89BKeiRgNK7xAAg6kJTPje uBm9PJTUxXaoaLJFXbYdSPfXhqX/BI9Xi2VzhwC2nSmizdFbeobQBTtRIz5LPhjk95t11q0s uP5htzNISPpwxiYZGKrNnXfcPlziI2bUtlz4ke34cLK6MIl1kbS0/kJBxhiXyvyTWk2JmkMi REjR84lCMAoJd1OM9XGFOg94BT5aLlEKFcld9qj7B4UFpma8RbRUpUWdo0omAEgrnhaKJwV8 qt0ULaF/kyP5qbI8iA2PAvIjq73dA4LNKdMFPG7Rw8yITQ1Vi0DlDgDT2RLvKxEQC0o3C6O4 iQq7qamsThLK0JSDRdLDnq6Phv+Yahd7sDMYuk3gIdoyczRkXzncWAYq7XTWl7nZYBVXG1D8 gkdclsnHzEKpTQIzn/rGyZshsjL4pxVUIpw/vdfx8oNRLKj7iduf11g2kFP71e9v2PP94ik3 Xi9oszP+fP770J0B8QM8w745BrcQm41SsILjArK+5mMHrYhM4ZFN7aipK3UXDNs3vjN+t0zi qErzlrxXtsX4J6nqjs/mF9frVkpv7OTAzj7pjFHv0Bu8pRm4AyW6Y5/H6jOup6nkJdP/AFDu 5ImdlA0jhr3iLk9s9WnjBUHyMYu+HD7qR3yhX6uWxg2oB2FWVMRLXbPEt2hRGq09rVQS7DBy dbZgPwou7pD8MTfQhGmDJFKm2jvOwU0EXchrcwEQAOsDQjdtPeaRt8EP2pc8tG+g9eiiX9Sh rX87SLSeKF6uHpEJ3VbhafIU6A7hy7RcIJnQz0hEUdXjH774B8YD3JKnAtfAyuIU2/rOGa/v UN4BY6U6TVIOv9piVQByBthGQh4YHhePSKtPzK9Pv/6rd8H3IWnJK/dXiUDQllkedrENXrZp eLUjhyp94ooo9XqRl44YqlsrSUh+BzW7wqwfmu26UjmAzIZYVCPCq5IjD96QrhLf6naY6En3 ++tqCAWPkqKvWfRdXPOz4GK08uhcBp3jZHTVkcbo5qahVpv8Y8mzOvSIAxnIjb+cklVxjyY9 dVlrhfKiK5L+zA2fWUreVBqLs1SjfHm5OGuQ2qqzVcMYJGH/uisJn22VXB1c48yYyGv2HUN5 lC1JHQUV9734I5cczA2Gfo27nTHy3zANj4hy+s/q1adzvn7hMokU7OehwKrNXafFfwWVK3OG 1dSjWtgIv5KJi1XZk5TV6JlPZSqj4D8pUwIx3KSp0cD7xTEZATRfc47Yc+cyKcXG034tNEAc xZNTR1kMi9njdxc1wzM9T6pspTtA0vuD3ee94Dg+nDrH1As24uwfFLguiILPzpl0kLaPYYgB wumlL2nGcB6RVRRFMiAS5uOTEk+sJ/tRiQwO3K8vmaECaNJRfJC7weH+jww1Dzo0f1TP6rUa fTBRABEBAAHCwXYEGAEIACAWIQRFRIIoLNkQ2+89Jfg+Xz0Ep6JGAwUCXchrcwIbDAAKCRA+ Xz0Ep6JGAxtdEAC54NQMBwjUNqBNCMsh6WrwQwbg9tkJw718QHPw43gKFSxFIYzdBzD/YMPH l+2fFiefvmI4uNDjlyCITGSM+T6b8cA7YAKvZhzJyJSS7pRzsIKGjhk7zADL1+PJei9p9idy RbmFKo0dAL+ac0t/EZULHGPuIiavWLgwYLVoUEBwz86ZtEtVmDmEsj8ryWw75ZIarNDhV74s BdM2ffUJk3+vWe25BPcJiaZkTuFt+xt2CdbvpZv3IPrEkp9GAKof2hHdFCRKMtgxBo8Kao6p Ws/Vv68FusAi94ySuZT3fp1xGWWf5+1jX4ylC//w0Rj85QihTpA2MylORUNFvH0MRJx4mlFk XN6G+5jIIJhG46LUucQ28+VyEDNcGL3tarnkw8ngEhAbnvMJ2RTx8vGh7PssKaGzAUmNNZiG MB4mPKqvDZ02j1wp7vthQcOEg08z1+XHXb8ZZKST7yTVa5P89JymGE8CBGdQaAXnqYK3/yWf FwRDcGV6nxanxZGKEkSHHOm8jHwvQWvPP73pvuPBEPtKGLzbgd7OOcGZWtq2hNC6cRtsRdDx 4TAGMCz4j238m+2mdbdhRh3iBnWT5yPFfnv/2IjFAk+sdix1Mrr+LIDF++kiekeq0yUpDdc4 ExBy2xf6dd+tuFFBp3/VDN4U0UfG4QJ2fg19zE5Z8dS4jGIbLg== In-Reply-To: <87ttjywxv5.wl-tiwai@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:HwANtY5pHX9qYll2jJJf4uOJIN+l61iXICErTSTzPZFd3Vw2k/u N1hnYThu6D0Km2BQUPRL5mUUfHMNfwVEgAbF1CZIeHZFIg8ncO4e3JTKGyHcwTroK23ibQA rE7IhaMGYIUrgTnljq/YB/bdaXefSM3CvV7JPwYb7uvdWmPSRsVYQ+qaoReJ5m5G5RW9Ghf /s2NNjCj0JSmKT7LjGvuQ== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:jG/myljbTF4=;XPgAA4qo5ZIYpJtOlwbLSQBsokR 6qH4ow+QPVJ+ryv/KBeGIP0ttNGiSC8lizgwQxwCRRct7do+0/oiRTFX+1onIOtT8z4QBIl07 UgzY9stE243qLk2UXNHvnNX2CLA8N+rztXofZoekxibMOZyfxrsx8wQ/uSohxV2Jg7+zRocA1 35flv2MaiKB9dBe4VS7Fscg0S9I3rEjfcikxNJ6orik0v+AjNmf8i1yT48ljDCb3pjL9usdES 56B4Cx7Az16c4AjkxdW14F/fTKX9SQAWCogHGks9/F3tbNVlZ8eic1oEvzMXsHtBylmjkYGpB IQ7mk7/2n9dg/IrxExBMT6bBWcW6bxDW+lePowFjUO3RwxbVOWoQrIj8S53IKoemvuaI/baBn GTdVBp36Ut6+K/X9KXiw3a5lfrnzBG9a1pOFh0Muy/apVFZjdqx5RVDubXDH8k1K2W5HgUmmt PY6lEN+9nJ77iD2Myi7uPM98nzpTgYOmsFYTXLGT6faFnh/h6sgzYY+kmppE+kKEqk+tESiXM YyG48Hq7Gx8WfKiZVQ6j8MD61U2qdOwiU9ELeIX/ipatw9+NzlGhYxcn7KGmZdv+KpfWW1qCW hmqTQnaxuWOKyfsz8CbAWryRK0R4TAfCqe/0XAeU6VsrElkEf3g2aO8hI3zoC0YoDJDbGdqmU j4Xttq98kVKPZYNYkXa9m/LT+QPumgaebWxv/qe1NBQSbE6BcwrSJO/j1dfZ1f6oEj4K990tN Z/AjgoygKtKeeEFX/jWv2miNB/2yGa08gF7EUjKJbqTFpqZIZc0CEUtAfCoBahUjuvxJunEtc 08RK2hk3ZyTqpITWf8ciiSZaCO6iCoaQuX4pP4n45UAic= On 4/18/24 16:26, Takashi Iwai wrote: > On Thu, 18 Apr 2024 16:06:52 +0200, > Nam Cao wrote: >> >> On 2024-04-18 Harshit Mogalapalli wrote: >>> While fuzzing 5.15.y kernel with Syzkaller, we noticed a INFO: task hu= ng >>> bug in fb_deferred_io_work() >> >> Which framebuffer device are you using exactly? It is possible that >> the problem is with the device driver, not core framebuffer. > > Note that it was already known that using flush_delayed_work() caused > a problem. See the thread of the fix patch: > https://lore.kernel.org/all/20230129082856.22113-1-tiwai@suse.de/ Harshit reported the hung tasks with kernel v5.15-stable, and can even rep= roduce that issue with kernel v6.9-rc4 although it has all of your patches from that referenced mail thread applied. So, what does your statement that "it was already known that it causes pro= blems" exactly mean? Can it be fixed? Is someone looking into fixing it? > BTW, the problem is seen with bochs drm. Helge