* Re: [PATCH v4 1/4] mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() [not found] ` <20250410204338.4b2101afdf18d8898390ef58@linux-foundation.org> @ 2025-04-11 5:32 ` Baoquan He 2025-04-11 15:07 ` Andreas Gruenbacher 0 siblings, 1 reply; 3+ messages in thread From: Baoquan He @ 2025-04-11 5:32 UTC (permalink / raw) To: Andrew Morton, agruenba, gfs2 Cc: linux-mm, david, osalvador, yanjun.zhu, linux-kernel On 04/10/25 at 08:43pm, Andrew Morton wrote: > On Thu, 10 Apr 2025 11:57:14 +0800 Baoquan He <bhe@redhat.com> wrote: > > > Not like fault_in_readable() or fault_in_writeable(), in > > fault_in_safe_writeable() local variable 'start' is increased page > > by page to loop till the whole address range is handled. However, > > it mistakenly calcalates the size of handled range with 'uaddr - start'. > > What are the userspace-visible runtime effects of this change? I see it mainly affect gfs2_file_direct_read(). Not sure if GFS2 people can sense any exceptional behaviour caused by this code bug. > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v4 1/4] mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() 2025-04-11 5:32 ` [PATCH v4 1/4] mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() Baoquan He @ 2025-04-11 15:07 ` Andreas Gruenbacher 2025-04-11 23:22 ` Andrew Morton 0 siblings, 1 reply; 3+ messages in thread From: Andreas Gruenbacher @ 2025-04-11 15:07 UTC (permalink / raw) To: Baoquan He Cc: Andrew Morton, gfs2, linux-mm, david, osalvador, yanjun.zhu, linux-kernel On Fri, Apr 11, 2025 at 7:32 AM Baoquan He <bhe@redhat.com> wrote: > On 04/10/25 at 08:43pm, Andrew Morton wrote: > > On Thu, 10 Apr 2025 11:57:14 +0800 Baoquan He <bhe@redhat.com> wrote: > > > > > Not like fault_in_readable() or fault_in_writeable(), in > > > fault_in_safe_writeable() local variable 'start' is increased page > > > by page to loop till the whole address range is handled. However, > > > it mistakenly calcalates the size of handled range with 'uaddr - start'. > > > > What are the userspace-visible runtime effects of this change? > > I see it mainly affect gfs2_file_direct_read(). Not sure if GFS2 people > can sense any exceptional behaviour caused by this code bug. Thanks for the heads up. In gfs2, fault_in_iov_iter_writeable() is used in gfs2_file_direct_read() and gfs2_file_read_iter(), so this potentially affects buffered as well as direct reads. This bug could cause those gfs2 functions to spin in a loop. Can this fix please be sent to Linus for inclusion into 6.15? Thanks, Andreas ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v4 1/4] mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() 2025-04-11 15:07 ` Andreas Gruenbacher @ 2025-04-11 23:22 ` Andrew Morton 0 siblings, 0 replies; 3+ messages in thread From: Andrew Morton @ 2025-04-11 23:22 UTC (permalink / raw) To: Andreas Gruenbacher Cc: Baoquan He, gfs2, linux-mm, david, osalvador, yanjun.zhu, linux-kernel On Fri, 11 Apr 2025 17:07:32 +0200 Andreas Gruenbacher <agruenba@redhat.com> wrote: > Can this fix please be sent to Linus for inclusion into 6.15? Sure, I made the adjustments. ^ permalink raw reply [flat|nested] 3+ messages in thread
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[not found] <20250410035717.473207-1-bhe@redhat.com>
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2025-04-11 5:32 ` [PATCH v4 1/4] mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable() Baoquan He
2025-04-11 15:07 ` Andreas Gruenbacher
2025-04-11 23:22 ` Andrew Morton
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