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Thu, 18 Apr 2024 14:26:13 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap1.dmz-prg2.suse.org with ESMTPSA id NqMFJoUtIWY0JAAAD6G6ig (envelope-from ); Thu, 18 Apr 2024 14:26:13 +0000 Date: Thu, 18 Apr 2024 16:26:22 +0200 Message-ID: <87ttjywxv5.wl-tiwai@suse.de> From: Takashi Iwai To: Nam Cao Cc: Harshit Mogalapalli , jayalk@intworks.biz, Daniel Vetter , deller@gmx.de, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, tiwai@suse.de, bigeasy@linutronix.de, patrik.r.jakobsson@gmail.com, LKML , Vegard Nossum , George Kennedy , Darren Kenny , chuansheng.liu@intel.com Subject: Re: [bug-report] task info hung problem in fb_deferred_io_work() In-Reply-To: <20240418160652.68df1a86@namcao> References: <271372d6-e665-4e7f-b088-dee5f4ab341a@oracle.com> <20240418160652.68df1a86@namcao> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-Spam-Flag: NO X-Spam-Score: -1.48 X-Spam-Level: X-Spamd-Result: default: False [-1.48 / 50.00]; BAYES_HAM(-2.68)[98.61%]; SUSPICIOUS_RECIPS(1.50)[]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; RCPT_COUNT_TWELVE(0.00)[15]; FREEMAIL_ENVRCPT(0.00)[gmail.com,gmx.de]; FREEMAIL_CC(0.00)[oracle.com,intworks.biz,ffwll.ch,gmx.de,vger.kernel.org,lists.freedesktop.org,suse.de,linutronix.de,gmail.com,intel.com]; RCVD_TLS_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] 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 hung > > 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/ BTW, the problem is seen with bochs drm. Takashi