Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-30 Thread Patrik Jakobsson
On Fri, Apr 19, 2024 at 5:34 PM Nam Cao wrote: > > On 2024-04-19 Patrik Jakobsson wrote: > > Neither cancel_delayed_work_sync() or flush_delayed_work() prevent new > > work from being scheduled after they return. > > flush_delayed_work() is called during device closing. And because no > writes

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Harshit Mogalapalli
On 19/04/24 21:53, Nam Cao wrote: On 2024-04-19 Harshit Mogalapalli wrote: +CC stable( heads up as this is a regression affecting 5.15.y and probably others, Greg: this was reproducible upstream so reported everything w.r.t upstream code but initially found on 5.15.y) No worry about this, I

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Nam Cao
On 2024-04-19 Harshit Mogalapalli wrote: > +CC stable( heads up as this is a regression affecting 5.15.y and > probably others, Greg: this was reproducible upstream so reported > everything w.r.t upstream code but initially found on 5.15.y) No worry about this, I will add a "Cc: " tag to the

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Harshit Mogalapalli
Hi Nam, +CC stable( heads up as this is a regression affecting 5.15.y and probably others, Greg: this was reproducible upstream so reported everything w.r.t upstream code but initially found on 5.15.y) On 19/04/24 20:29, Nam Cao wrote: On 2024-04-18 Harshit Mogalapalli wrote: While

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Nam Cao
On 2024-04-19 Patrik Jakobsson wrote: > Neither cancel_delayed_work_sync() or flush_delayed_work() prevent new > work from being scheduled after they return. flush_delayed_work() is called during device closing. And because no writes are performed after the device has been closed, no new work

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Nam Cao
On 2024-04-18 Patrik Jakobsson wrote: > On Thu, Apr 18, 2024 at 4:05 PM Nam Cao wrote: > > > > On 2024-04-18 Patrik Jakobsson wrote: > > > This sounds similar to the SUSE bug [1]. We fixed it by reverting [2] > > > in the SUSE kernel. The problem seems to be that flush_delayed_work() > > >

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Nam Cao
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() I think the problem is because of improper offset address calculation. The kernel calculate address offset with: offset = vmf->address -

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Harshit Mogalapalli
Hi Takashi, On 19/04/24 13:15, Takashi Iwai wrote: On Fri, 19 Apr 2024 09:39:09 +0200, Then later on, the commit 33cd6ea9c067 changed cancel_*() to flush_delayed_work() blindly, and the known problem resurfaced again. I have reverted that commit, but still could see some other task hung

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Patrik Jakobsson
On Fri, Apr 19, 2024 at 9:45 AM Takashi Iwai wrote: > > On Fri, 19 Apr 2024 09:39:09 +0200, > Harshit Mogalapalli wrote: > > > > Hi Takashi, > > > > On 19/04/24 12:14, Takashi Iwai wrote: > > > On Thu, 18 Apr 2024 21:29:57 +0200, > > > Helge Deller wrote: > > >> > > >> On 4/18/24 16:26, Takashi

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Takashi Iwai
On Fri, 19 Apr 2024 09:39:09 +0200, Harshit Mogalapalli wrote: > > Hi Takashi, > > On 19/04/24 12:14, Takashi Iwai wrote: > > On Thu, 18 Apr 2024 21:29:57 +0200, > > Helge Deller wrote: > >> > >> On 4/18/24 16:26, Takashi Iwai wrote: > >>> On Thu, 18 Apr 2024 16:06:52 +0200, > >>> Nam Cao

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Harshit Mogalapalli
Hi Takashi, On 19/04/24 12:14, Takashi Iwai wrote: On Thu, 18 Apr 2024 21:29:57 +0200, Helge Deller wrote: 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

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Harshit Mogalapalli
Hi Nam, On 18/04/24 19:36, 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,

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Harshit Mogalapalli
Hi Patrik, On 18/04/24 18:44, Patrik Jakobsson wrote: On Thu, Apr 18, 2024 at 2:40 PM Harshit Mogalapalli wrote: Hi, While fuzzing 5.15.y kernel with Syzkaller, we noticed a INFO: task hung bug in fb_deferred_io_work() This is in 5.15.149 tag, and this is introduced by a set of commits:

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-19 Thread Takashi Iwai
On Thu, 18 Apr 2024 21:29:57 +0200, Helge Deller wrote: > > 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 hung > >>> bug

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-18 Thread Helge Deller
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 hung bug in fb_deferred_io_work() Which framebuffer device are you using exactly? It is

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-18 Thread Patrik Jakobsson
On Thu, Apr 18, 2024 at 4:05 PM Nam Cao wrote: > > On 2024-04-18 Patrik Jakobsson wrote: > > This sounds similar to the SUSE bug [1]. We fixed it by reverting [2] > > in the SUSE kernel. The problem seems to be that flush_delayed_work() > > kills the timer and re-queues the work but doesn't

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-18 Thread Takashi Iwai
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

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-18 Thread Nam Cao
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. Best regards, Nam

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-18 Thread Nam Cao
On 2024-04-18 Patrik Jakobsson wrote: > This sounds similar to the SUSE bug [1]. We fixed it by reverting [2] > in the SUSE kernel. The problem seems to be that flush_delayed_work() > kills the timer and re-queues the work but doesn't guarantee that it > is finished when returning. So when the

Re: [bug-report] task info hung problem in fb_deferred_io_work()

2024-04-18 Thread Patrik Jakobsson
On Thu, Apr 18, 2024 at 2:40 PM Harshit Mogalapalli wrote: > > Hi, > > While fuzzing 5.15.y kernel with Syzkaller, we noticed a INFO: task hung > bug in fb_deferred_io_work() > > > This is in 5.15.149 tag, and this is introduced by a set of commits: > > 2655757a3f10 fbdev: flush deferred IO

[bug-report] task info hung problem in fb_deferred_io_work()

2024-04-18 Thread Harshit Mogalapalli
Hi, While fuzzing 5.15.y kernel with Syzkaller, we noticed a INFO: task hung bug in fb_deferred_io_work() This is in 5.15.149 tag, and this is introduced by a set of commits: 2655757a3f10 fbdev: flush deferred IO before closing 15492bab7393 fbdev: Fix incorrect page mapping clearance at