From: Michal Hocko <mhocko@kernel.org> To: Wei Yang <richard.weiyang@gmail.com> Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/vmalloc: a slight change of compare target in __insert_vmap_area() Date: Wed, 24 May 2017 14:11:35 +0200 [thread overview] Message-ID: <20170524121135.GF14733@dhcp22.suse.cz> (raw) In-Reply-To: <20170524100347.8131-1-richard.weiyang@gmail.com> On Wed 24-05-17 18:03:47, Wei Yang wrote: > The vmap RB tree store the elements in order and no overlap between any of > them. The comparison in __insert_vmap_area() is to decide which direction > the search should follow and make sure the new vmap_area is not overlap > with any other. > > Current implementation fails to do the overlap check. > > When first "if" is not true, it means > > va->va_start >= tmp_va->va_end > > And with the truth > > xxx->va_end > xxx->va_start > > The deduction is > > va->va_end > tmp_va->va_start > > which is the condition in second "if". > > This patch changes a little of the comparison in __insert_vmap_area() to > make sure it forbids the overlapped vmap_area. Why do we care about overlapping vmap areas at this level. This is an internal function and all the sanity checks should have been done by that time AFAIR. Could you describe the problem which you are trying to fix/address? > Signed-off-by: Wei Yang <richard.weiyang@gmail.com> > --- > mm/vmalloc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 0b057628a7ba..8087451cb332 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -360,9 +360,9 @@ static void __insert_vmap_area(struct vmap_area *va) > > parent = *p; > tmp_va = rb_entry(parent, struct vmap_area, rb_node); > - if (va->va_start < tmp_va->va_end) > + if (va->va_end <= tmp_va->va_start) > p = &(*p)->rb_left; > - else if (va->va_end > tmp_va->va_start) > + else if (va->va_start >= tmp_va->va_end) > p = &(*p)->rb_right; > else > BUG(); > -- > 2.11.0 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> -- Michal Hocko SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org> To: Wei Yang <richard.weiyang@gmail.com> Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/vmalloc: a slight change of compare target in __insert_vmap_area() Date: Wed, 24 May 2017 14:11:35 +0200 [thread overview] Message-ID: <20170524121135.GF14733@dhcp22.suse.cz> (raw) In-Reply-To: <20170524100347.8131-1-richard.weiyang@gmail.com> On Wed 24-05-17 18:03:47, Wei Yang wrote: > The vmap RB tree store the elements in order and no overlap between any of > them. The comparison in __insert_vmap_area() is to decide which direction > the search should follow and make sure the new vmap_area is not overlap > with any other. > > Current implementation fails to do the overlap check. > > When first "if" is not true, it means > > va->va_start >= tmp_va->va_end > > And with the truth > > xxx->va_end > xxx->va_start > > The deduction is > > va->va_end > tmp_va->va_start > > which is the condition in second "if". > > This patch changes a little of the comparison in __insert_vmap_area() to > make sure it forbids the overlapped vmap_area. Why do we care about overlapping vmap areas at this level. This is an internal function and all the sanity checks should have been done by that time AFAIR. Could you describe the problem which you are trying to fix/address? > Signed-off-by: Wei Yang <richard.weiyang@gmail.com> > --- > mm/vmalloc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 0b057628a7ba..8087451cb332 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -360,9 +360,9 @@ static void __insert_vmap_area(struct vmap_area *va) > > parent = *p; > tmp_va = rb_entry(parent, struct vmap_area, rb_node); > - if (va->va_start < tmp_va->va_end) > + if (va->va_end <= tmp_va->va_start) > p = &(*p)->rb_left; > - else if (va->va_end > tmp_va->va_start) > + else if (va->va_start >= tmp_va->va_end) > p = &(*p)->rb_right; > else > BUG(); > -- > 2.11.0 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-05-24 12:11 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-05-24 10:03 [PATCH] mm/vmalloc: a slight change of compare target in __insert_vmap_area() Wei Yang 2017-05-24 10:03 ` Wei Yang 2017-05-24 12:11 ` Michal Hocko [this message] 2017-05-24 12:11 ` Michal Hocko 2017-05-24 15:07 ` Wei Yang 2017-05-25 5:39 ` Michal Hocko 2017-05-25 5:39 ` Michal Hocko 2017-05-25 3:04 ` zhong jiang 2017-05-25 3:04 ` zhong jiang 2017-05-26 1:36 ` Wei Yang 2017-05-26 1:55 ` zhong jiang 2017-05-26 1:55 ` zhong jiang 2017-06-02 1:45 ` Wei Yang 2017-06-02 2:26 ` zhong jiang 2017-06-02 2:26 ` zhong jiang 2017-06-03 2:28 ` Wei Yang
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20170524121135.GF14733@dhcp22.suse.cz \ --to=mhocko@kernel.org \ --cc=akpm@linux-foundation.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=richard.weiyang@gmail.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.