* [uml-devel] [PATCH 1/1] hostfs: fix UML crash @ 2010-10-18 16:36 ` Richard Weinberger 0 siblings, 0 replies; 15+ messages in thread From: Richard Weinberger @ 2010-10-18 16:36 UTC (permalink / raw) To: akpm Cc: user-mode-linux-devel, Richard Weinberger, jdike, linux-kernel, viro, toralf.foerster 365b1818 resized f_spare within struct statfs. hostfs accesses f_spare directly and needs an update. Signed-off-by: Richard Weinberger <richard@nod.at> Reported-by: Toralf Förster <toralf.foerster@gmx.de> Tested-by: Toralf Förster <toralf.foerster@gmx.de> --- fs/hostfs/hostfs_user.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c index 6777aa0..ce2f168 100644 --- a/fs/hostfs/hostfs_user.c +++ b/fs/hostfs/hostfs_user.c @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long *blocks_out, spare_out[1] = buf.f_spare[1]; spare_out[2] = buf.f_spare[2]; spare_out[3] = buf.f_spare[3]; - spare_out[4] = buf.f_spare[4]; + return 0; } -- 1.6.6.1 ------------------------------------------------------------------------------ Download new Adobe(R) Flash(R) Builder(TM) 4 The new Adobe(R) Flex(R) 4 and Flash(R) Builder(TM) 4 (formerly Flex(R) Builder(TM)) enable the development of rich applications that run across multiple browsers and platforms. Download your free trials today! http://p.sf.net/sfu/adobe-dev2dev _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply related [flat|nested] 15+ messages in thread
* [PATCH 1/1] hostfs: fix UML crash @ 2010-10-18 16:36 ` Richard Weinberger 0 siblings, 0 replies; 15+ messages in thread From: Richard Weinberger @ 2010-10-18 16:36 UTC (permalink / raw) To: akpm Cc: linux-kernel, jdike, user-mode-linux-devel, viro, toralf.foerster, Richard Weinberger 365b1818 resized f_spare within struct statfs. hostfs accesses f_spare directly and needs an update. Signed-off-by: Richard Weinberger <richard@nod.at> Reported-by: Toralf Förster <toralf.foerster@gmx.de> Tested-by: Toralf Förster <toralf.foerster@gmx.de> --- fs/hostfs/hostfs_user.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c index 6777aa0..ce2f168 100644 --- a/fs/hostfs/hostfs_user.c +++ b/fs/hostfs/hostfs_user.c @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long *blocks_out, spare_out[1] = buf.f_spare[1]; spare_out[2] = buf.f_spare[2]; spare_out[3] = buf.f_spare[3]; - spare_out[4] = buf.f_spare[4]; + return 0; } -- 1.6.6.1 ^ permalink raw reply related [flat|nested] 15+ messages in thread
* Re: [uml-devel] [PATCH 1/1] hostfs: fix UML crash 2010-10-18 16:36 ` Richard Weinberger @ 2010-10-18 18:40 ` Andrew Morton -1 siblings, 0 replies; 15+ messages in thread From: Andrew Morton @ 2010-10-18 18:40 UTC (permalink / raw) To: Richard Weinberger Cc: toralf.foerster, jdike, linux-kernel, user-mode-linux-devel, viro On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> wrote: > 365b1818 resized f_spare within struct statfs. > hostfs accesses f_spare directly and needs an update. > > Signed-off-by: Richard Weinberger <richard@nod.at> > Reported-by: Toralf F__rster <toralf.foerster@gmx.de> > Tested-by: Toralf F__rster <toralf.foerster@gmx.de> > --- > fs/hostfs/hostfs_user.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c > index 6777aa0..ce2f168 100644 > --- a/fs/hostfs/hostfs_user.c > +++ b/fs/hostfs/hostfs_user.c > @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long *blocks_out, > spare_out[1] = buf.f_spare[1]; > spare_out[2] = buf.f_spare[2]; > spare_out[3] = buf.f_spare[3]; > - spare_out[4] = buf.f_spare[4]; > + > return 0; > } Thanks. Is there any reason for hostfs to be playing with the f_spare field at all? ------------------------------------------------------------------------------ Download new Adobe(R) Flash(R) Builder(TM) 4 The new Adobe(R) Flex(R) 4 and Flash(R) Builder(TM) 4 (formerly Flex(R) Builder(TM)) enable the development of rich applications that run across multiple browsers and platforms. Download your free trials today! http://p.sf.net/sfu/adobe-dev2dev _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/1] hostfs: fix UML crash @ 2010-10-18 18:40 ` Andrew Morton 0 siblings, 0 replies; 15+ messages in thread From: Andrew Morton @ 2010-10-18 18:40 UTC (permalink / raw) To: Richard Weinberger Cc: linux-kernel, jdike, user-mode-linux-devel, viro, toralf.foerster On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> wrote: > 365b1818 resized f_spare within struct statfs. > hostfs accesses f_spare directly and needs an update. > > Signed-off-by: Richard Weinberger <richard@nod.at> > Reported-by: Toralf F__rster <toralf.foerster@gmx.de> > Tested-by: Toralf F__rster <toralf.foerster@gmx.de> > --- > fs/hostfs/hostfs_user.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c > index 6777aa0..ce2f168 100644 > --- a/fs/hostfs/hostfs_user.c > +++ b/fs/hostfs/hostfs_user.c > @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long *blocks_out, > spare_out[1] = buf.f_spare[1]; > spare_out[2] = buf.f_spare[2]; > spare_out[3] = buf.f_spare[3]; > - spare_out[4] = buf.f_spare[4]; > + > return 0; > } Thanks. Is there any reason for hostfs to be playing with the f_spare field at all? ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/1] hostfs: fix UML crash 2010-10-18 18:40 ` Andrew Morton (?) @ 2010-10-18 18:53 ` Richard Weinberger 2010-10-18 20:02 ` Andrew Morton -1 siblings, 1 reply; 15+ messages in thread From: Richard Weinberger @ 2010-10-18 18:53 UTC (permalink / raw) To: Andrew Morton Cc: linux-kernel, jdike, user-mode-linux-devel, viro, toralf.foerster Am Montag 18 Oktober 2010, 20:40:39 schrieb Andrew Morton: > On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> wrote: > > 365b1818 resized f_spare within struct statfs. > > hostfs accesses f_spare directly and needs an update. > > > > Signed-off-by: Richard Weinberger <richard@nod.at> > > Reported-by: Toralf F__rster <toralf.foerster@gmx.de> > > Tested-by: Toralf F__rster <toralf.foerster@gmx.de> > > --- > > > > fs/hostfs/hostfs_user.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c > > index 6777aa0..ce2f168 100644 > > --- a/fs/hostfs/hostfs_user.c > > +++ b/fs/hostfs/hostfs_user.c > > @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long > > *blocks_out, > > > > spare_out[1] = buf.f_spare[1]; > > spare_out[2] = buf.f_spare[2]; > > spare_out[3] = buf.f_spare[3]; > > > > - spare_out[4] = buf.f_spare[4]; > > + > > > > return 0; > > > > } > > Thanks. > > Is there any reason for hostfs to be playing with the f_spare field at all? I'm not sure why hostfs is using this field. Currently I'm reviewing UML. As soon I'm done with hostfs you'll receive a patch or an explanation. :-) Cheers, //richard ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [PATCH 1/1] hostfs: fix UML crash 2010-10-18 18:53 ` Richard Weinberger @ 2010-10-18 20:02 ` Andrew Morton 0 siblings, 0 replies; 15+ messages in thread From: Andrew Morton @ 2010-10-18 20:02 UTC (permalink / raw) To: Richard Weinberger Cc: Arnd Bergmann, user-mode-linux-devel, toralf.foerster, jdike, linux-kernel, viro, Christoph Hellwig On Mon, 18 Oct 2010 20:53:58 +0200 Richard Weinberger <richard@nod.at> wrote: > Am Montag 18 Oktober 2010, 20:40:39 schrieb Andrew Morton: > > On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> > wrote: > > > 365b1818 resized f_spare within struct statfs. > > > hostfs accesses f_spare directly and needs an update. > > > > > > Signed-off-by: Richard Weinberger <richard@nod.at> > > > Reported-by: Toralf F__rster <toralf.foerster@gmx.de> > > > Tested-by: Toralf F__rster <toralf.foerster@gmx.de> > > > --- > > > > > > fs/hostfs/hostfs_user.c | 2 +- > > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > > > diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c > > > index 6777aa0..ce2f168 100644 > > > --- a/fs/hostfs/hostfs_user.c > > > +++ b/fs/hostfs/hostfs_user.c > > > @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long > > > *blocks_out, > > > > > > spare_out[1] = buf.f_spare[1]; > > > spare_out[2] = buf.f_spare[2]; > > > spare_out[3] = buf.f_spare[3]; > > > > > > - spare_out[4] = buf.f_spare[4]; > > > + > > > > > > return 0; > > > > > > } > > > > Thanks. > > > > Is there any reason for hostfs to be playing with the f_spare field at all? > > I'm not sure why hostfs is using this field. > Currently I'm reviewing UML. > As soon I'm done with hostfs you'll receive a patch or an explanation. :-) 365b1818 added f_flags to `struct statfs' but didn't carry that over to `struct compat_statfs' and hence didn't copy f_flags over into compat_statfs. Deliberate, or oversight? ------------------------------------------------------------------------------ Download new Adobe(R) Flash(R) Builder(TM) 4 The new Adobe(R) Flex(R) 4 and Flash(R) Builder(TM) 4 (formerly Flex(R) Builder(TM)) enable the development of rich applications that run across multiple browsers and platforms. Download your free trials today! http://p.sf.net/sfu/adobe-dev2dev _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/1] hostfs: fix UML crash @ 2010-10-18 20:02 ` Andrew Morton 0 siblings, 0 replies; 15+ messages in thread From: Andrew Morton @ 2010-10-18 20:02 UTC (permalink / raw) To: Richard Weinberger Cc: linux-kernel, jdike, user-mode-linux-devel, viro, toralf.foerster, Christoph Hellwig, Arnd Bergmann On Mon, 18 Oct 2010 20:53:58 +0200 Richard Weinberger <richard@nod.at> wrote: > Am Montag 18 Oktober 2010, 20:40:39 schrieb Andrew Morton: > > On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> > wrote: > > > 365b1818 resized f_spare within struct statfs. > > > hostfs accesses f_spare directly and needs an update. > > > > > > Signed-off-by: Richard Weinberger <richard@nod.at> > > > Reported-by: Toralf F__rster <toralf.foerster@gmx.de> > > > Tested-by: Toralf F__rster <toralf.foerster@gmx.de> > > > --- > > > > > > fs/hostfs/hostfs_user.c | 2 +- > > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > > > diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c > > > index 6777aa0..ce2f168 100644 > > > --- a/fs/hostfs/hostfs_user.c > > > +++ b/fs/hostfs/hostfs_user.c > > > @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long > > > *blocks_out, > > > > > > spare_out[1] = buf.f_spare[1]; > > > spare_out[2] = buf.f_spare[2]; > > > spare_out[3] = buf.f_spare[3]; > > > > > > - spare_out[4] = buf.f_spare[4]; > > > + > > > > > > return 0; > > > > > > } > > > > Thanks. > > > > Is there any reason for hostfs to be playing with the f_spare field at all? > > I'm not sure why hostfs is using this field. > Currently I'm reviewing UML. > As soon I'm done with hostfs you'll receive a patch or an explanation. :-) 365b1818 added f_flags to `struct statfs' but didn't carry that over to `struct compat_statfs' and hence didn't copy f_flags over into compat_statfs. Deliberate, or oversight? ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [PATCH 1/1] hostfs: fix UML crash 2010-10-18 20:02 ` Andrew Morton @ 2010-10-19 1:11 ` Christoph Hellwig -1 siblings, 0 replies; 15+ messages in thread From: Christoph Hellwig @ 2010-10-19 1:11 UTC (permalink / raw) To: Andrew Morton Cc: Arnd Bergmann, user-mode-linux-devel, toralf.foerster, jdike, linux-kernel, viro, Richard Weinberger, Christoph Hellwig On Mon, Oct 18, 2010 at 01:02:08PM -0700, Andrew Morton wrote: > > > > > > Is there any reason for hostfs to be playing with the f_spare field at all? No, there is no reason at all. do_statfs is only called by hostfs_statfs, which is the hostfs implementation of ->statfs. zeroing of the spare fields is done by common code (vfs_statfs_native). Can you submit a patch to just remove the spare_out argument to do_statfs? > 365b1818 added f_flags to `struct statfs' but didn't carry that over to > `struct compat_statfs' and hence didn't copy f_flags over into > compat_statfs. Deliberate, or oversight? Oversight. ------------------------------------------------------------------------------ Download new Adobe(R) Flash(R) Builder(TM) 4 The new Adobe(R) Flex(R) 4 and Flash(R) Builder(TM) 4 (formerly Flex(R) Builder(TM)) enable the development of rich applications that run across multiple browsers and platforms. Download your free trials today! http://p.sf.net/sfu/adobe-dev2dev _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/1] hostfs: fix UML crash @ 2010-10-19 1:11 ` Christoph Hellwig 0 siblings, 0 replies; 15+ messages in thread From: Christoph Hellwig @ 2010-10-19 1:11 UTC (permalink / raw) To: Andrew Morton Cc: Richard Weinberger, linux-kernel, jdike, user-mode-linux-devel, viro, toralf.foerster, Christoph Hellwig, Arnd Bergmann On Mon, Oct 18, 2010 at 01:02:08PM -0700, Andrew Morton wrote: > > > > > > Is there any reason for hostfs to be playing with the f_spare field at all? No, there is no reason at all. do_statfs is only called by hostfs_statfs, which is the hostfs implementation of ->statfs. zeroing of the spare fields is done by common code (vfs_statfs_native). Can you submit a patch to just remove the spare_out argument to do_statfs? > 365b1818 added f_flags to `struct statfs' but didn't carry that over to > `struct compat_statfs' and hence didn't copy f_flags over into > compat_statfs. Deliberate, or oversight? Oversight. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/1] hostfs: fix UML crash 2010-10-19 1:11 ` Christoph Hellwig @ 2010-10-19 10:27 ` Richard Weinberger -1 siblings, 0 replies; 15+ messages in thread From: Richard Weinberger @ 2010-10-19 10:27 UTC (permalink / raw) To: Christoph Hellwig Cc: Andrew Morton, linux-kernel, jdike, user-mode-linux-devel, viro, toralf.foerster, Arnd Bergmann On Tue, 19 Oct 2010 03:11:25 +0200, Christoph Hellwig <hch@lst.de> wrote: > On Mon, Oct 18, 2010 at 01:02:08PM -0700, Andrew Morton wrote: >> > > >> > > Is there any reason for hostfs to be playing with the f_spare field at all? > > No, there is no reason at all. do_statfs is only called by > hostfs_statfs, which is the hostfs implementation of ->statfs. zeroing > of the spare fields is done by common code (vfs_statfs_native). Thanks! > Can you submit a patch to just remove the spare_out argument to do_statfs? Sure. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH 1/1] hostfs: fix UML crash @ 2010-10-19 10:27 ` Richard Weinberger 0 siblings, 0 replies; 15+ messages in thread From: Richard Weinberger @ 2010-10-19 10:27 UTC (permalink / raw) To: Christoph Hellwig Cc: Andrew Morton, linux-kernel, jdike, user-mode-linux-devel, viro, toralf.foerster, Arnd Bergmann On Tue, 19 Oct 2010 03:11:25 +0200, Christoph Hellwig <hch@lst.de> wrote: > On Mon, Oct 18, 2010 at 01:02:08PM -0700, Andrew Morton wrote: >> > > >> > > Is there any reason for hostfs to be playing with the f_spare field at all? > > No, there is no reason at all. do_statfs is only called by > hostfs_statfs, which is the hostfs implementation of ->statfs. zeroing > of the spare fields is done by common code (vfs_statfs_native). Thanks! > Can you submit a patch to just remove the spare_out argument to do_statfs? Sure. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [PATCH 1/1] hostfs: fix UML crash 2010-10-18 18:40 ` Andrew Morton (?) (?) @ 2010-10-18 19:22 ` Geert Uytterhoeven 2010-10-18 19:31 ` Richard Weinberger -1 siblings, 1 reply; 15+ messages in thread From: Geert Uytterhoeven @ 2010-10-18 19:22 UTC (permalink / raw) To: Andrew Morton Cc: Richard Weinberger, toralf.foerster, jdike, linux-kernel, user-mode-linux-devel, viro On Mon, Oct 18, 2010 at 20:40, Andrew Morton <akpm@linux-foundation.org> wrote: > On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> wrote: >> 365b1818 resized f_spare within struct statfs. >> hostfs accesses f_spare directly and needs an update. >> >> Signed-off-by: Richard Weinberger <richard@nod.at> >> Reported-by: Toralf F__rster <toralf.foerster@gmx.de> >> Tested-by: Toralf F__rster <toralf.foerster@gmx.de> >> --- >> fs/hostfs/hostfs_user.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c >> index 6777aa0..ce2f168 100644 >> --- a/fs/hostfs/hostfs_user.c >> +++ b/fs/hostfs/hostfs_user.c >> @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long *blocks_out, >> spare_out[1] = buf.f_spare[1]; >> spare_out[2] = buf.f_spare[2]; >> spare_out[3] = buf.f_spare[3]; >> - spare_out[4] = buf.f_spare[4]; >> + >> return 0; >> } > > Thanks. > > Is there any reason for hostfs to be playing with the f_spare field at all? It just copies it from struct statfs64 on the host to struct kstatfs on the guest. Probably a memcpy() is more future-safe, if it's combined with a BUILD_BUG_ON(sizeof(statfs64.f_spare) != sizeof(kstatfs.f_spare)). Still, currently it doesn't copy the recently added f_flags field. To protect against future changes like that, an explicit BUILD_BUG_ON(sizeof(kstatfs.f_spare) != 4*sizeof(long)) may be even better... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [PATCH 1/1] hostfs: fix UML crash 2010-10-18 19:22 ` [uml-devel] " Geert Uytterhoeven @ 2010-10-18 19:31 ` Richard Weinberger 2010-10-18 19:43 ` Geert Uytterhoeven 0 siblings, 1 reply; 15+ messages in thread From: Richard Weinberger @ 2010-10-18 19:31 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Andrew Morton, toralf.foerster, jdike, linux-kernel, user-mode-linux-devel, viro Am Montag 18 Oktober 2010, 21:22:31 schrieb Geert Uytterhoeven: > On Mon, Oct 18, 2010 at 20:40, Andrew Morton <akpm@linux-foundation.org> wrote: > > On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> wrote: > >> 365b1818 resized f_spare within struct statfs. > >> hostfs accesses f_spare directly and needs an update. > >> > >> Signed-off-by: Richard Weinberger <richard@nod.at> > >> Reported-by: Toralf F__rster <toralf.foerster@gmx.de> > >> Tested-by: Toralf F__rster <toralf.foerster@gmx.de> > >> --- > >> fs/hostfs/hostfs_user.c | 2 +- > >> 1 files changed, 1 insertions(+), 1 deletions(-) > >> > >> diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c > >> index 6777aa0..ce2f168 100644 > >> --- a/fs/hostfs/hostfs_user.c > >> +++ b/fs/hostfs/hostfs_user.c > >> @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long > >> *blocks_out, spare_out[1] = buf.f_spare[1]; > >> spare_out[2] = buf.f_spare[2]; > >> spare_out[3] = buf.f_spare[3]; > >> - spare_out[4] = buf.f_spare[4]; > >> + > >> return 0; > >> } > > > > Thanks. > > > > Is there any reason for hostfs to be playing with the f_spare field at > > all? > > It just copies it from struct statfs64 on the host to struct kstatfs > on the guest. > Probably a memcpy() is more future-safe, if it's combined with a > BUILD_BUG_ON(sizeof(statfs64.f_spare) != sizeof(kstatfs.f_spare)). > > Still, currently it doesn't copy the recently added f_flags field. > To protect against future changes like that, an explicit > BUILD_BUG_ON(sizeof(kstatfs.f_spare) != 4*sizeof(long)) may be even > better... Anyway, why do we need to copy f_spare from the host to the guest? I'm quite sure it can be omitted. Thanks, //richard ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [PATCH 1/1] hostfs: fix UML crash 2010-10-18 19:31 ` Richard Weinberger @ 2010-10-18 19:43 ` Geert Uytterhoeven 2010-10-18 20:03 ` Richard Weinberger 0 siblings, 1 reply; 15+ messages in thread From: Geert Uytterhoeven @ 2010-10-18 19:43 UTC (permalink / raw) To: Richard Weinberger Cc: Andrew Morton, toralf.foerster, jdike, linux-kernel, user-mode-linux-devel, viro On Mon, Oct 18, 2010 at 21:31, Richard Weinberger <richard@nod.at> wrote: > Am Montag 18 Oktober 2010, 21:22:31 schrieb Geert Uytterhoeven: >> On Mon, Oct 18, 2010 at 20:40, Andrew Morton <akpm@linux-foundation.org> > wrote: >> > On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> > wrote: >> >> 365b1818 resized f_spare within struct statfs. >> >> hostfs accesses f_spare directly and needs an update. >> >> >> >> Signed-off-by: Richard Weinberger <richard@nod.at> >> >> Reported-by: Toralf F__rster <toralf.foerster@gmx.de> >> >> Tested-by: Toralf F__rster <toralf.foerster@gmx.de> >> >> --- >> >> fs/hostfs/hostfs_user.c | 2 +- >> >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> >> >> diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c >> >> index 6777aa0..ce2f168 100644 >> >> --- a/fs/hostfs/hostfs_user.c >> >> +++ b/fs/hostfs/hostfs_user.c >> >> @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long >> >> *blocks_out, spare_out[1] = buf.f_spare[1]; >> >> spare_out[2] = buf.f_spare[2]; >> >> spare_out[3] = buf.f_spare[3]; >> >> - spare_out[4] = buf.f_spare[4]; >> >> + >> >> return 0; >> >> } >> > >> > Thanks. >> > >> > Is there any reason for hostfs to be playing with the f_spare field at >> > all? >> >> It just copies it from struct statfs64 on the host to struct kstatfs >> on the guest. >> Probably a memcpy() is more future-safe, if it's combined with a >> BUILD_BUG_ON(sizeof(statfs64.f_spare) != sizeof(kstatfs.f_spare)). >> >> Still, currently it doesn't copy the recently added f_flags field. >> To protect against future changes like that, an explicit >> BUILD_BUG_ON(sizeof(kstatfs.f_spare) != 4*sizeof(long)) may be even >> better... > > Anyway, why do we need to copy f_spare from the host to the guest? > I'm quite sure it can be omitted. I guess it wants to preserve fields that are added in the future, which may be useful if the host is more recent than the guest. Still, even if you don't want to preserve them, you probably want to clear them, so memset() is better than a fixed loop through 4 elements. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [uml-devel] [PATCH 1/1] hostfs: fix UML crash 2010-10-18 19:43 ` Geert Uytterhoeven @ 2010-10-18 20:03 ` Richard Weinberger 0 siblings, 0 replies; 15+ messages in thread From: Richard Weinberger @ 2010-10-18 20:03 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Andrew Morton, toralf.foerster, jdike, linux-kernel, user-mode-linux-devel, viro Am Montag 18 Oktober 2010, 21:43:44 schrieb Geert Uytterhoeven: > On Mon, Oct 18, 2010 at 21:31, Richard Weinberger <richard@nod.at> wrote: > > Am Montag 18 Oktober 2010, 21:22:31 schrieb Geert Uytterhoeven: > >> On Mon, Oct 18, 2010 at 20:40, Andrew Morton <akpm@linux-foundation.org> > > > > wrote: > >> > On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> > > > > wrote: > >> >> 365b1818 resized f_spare within struct statfs. > >> >> hostfs accesses f_spare directly and needs an update. > >> >> > >> >> Signed-off-by: Richard Weinberger <richard@nod.at> > >> >> Reported-by: Toralf F__rster <toralf.foerster@gmx.de> > >> >> Tested-by: Toralf F__rster <toralf.foerster@gmx.de> > >> >> --- > >> >> fs/hostfs/hostfs_user.c | 2 +- > >> >> 1 files changed, 1 insertions(+), 1 deletions(-) > >> >> > >> >> diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c > >> >> index 6777aa0..ce2f168 100644 > >> >> --- a/fs/hostfs/hostfs_user.c > >> >> +++ b/fs/hostfs/hostfs_user.c > >> >> @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long > >> >> long *blocks_out, spare_out[1] = buf.f_spare[1]; > >> >> spare_out[2] = buf.f_spare[2]; > >> >> spare_out[3] = buf.f_spare[3]; > >> >> - spare_out[4] = buf.f_spare[4]; > >> >> + > >> >> return 0; > >> >> } > >> > > >> > Thanks. > >> > > >> > Is there any reason for hostfs to be playing with the f_spare field at > >> > all? > >> > >> It just copies it from struct statfs64 on the host to struct kstatfs > >> on the guest. > >> Probably a memcpy() is more future-safe, if it's combined with a > >> BUILD_BUG_ON(sizeof(statfs64.f_spare) != sizeof(kstatfs.f_spare)). > >> > >> Still, currently it doesn't copy the recently added f_flags field. > >> To protect against future changes like that, an explicit > >> BUILD_BUG_ON(sizeof(kstatfs.f_spare) != 4*sizeof(long)) may be even > >> better... IMHO using kstatfs within ubd_user.c is not very nice because is a internal kernel struct. > > Anyway, why do we need to copy f_spare from the host to the guest? > > I'm quite sure it can be omitted. > > I guess it wants to preserve fields that are added in the future, > which may be useful > if the host is more recent than the guest. Good point! Thanks, //richard ^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2010-10-19 10:27 UTC | newest] Thread overview: 15+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2010-10-18 16:36 [uml-devel] [PATCH 1/1] hostfs: fix UML crash Richard Weinberger 2010-10-18 16:36 ` Richard Weinberger 2010-10-18 18:40 ` [uml-devel] " Andrew Morton 2010-10-18 18:40 ` Andrew Morton 2010-10-18 18:53 ` Richard Weinberger 2010-10-18 20:02 ` [uml-devel] " Andrew Morton 2010-10-18 20:02 ` Andrew Morton 2010-10-19 1:11 ` [uml-devel] " Christoph Hellwig 2010-10-19 1:11 ` Christoph Hellwig 2010-10-19 10:27 ` Richard Weinberger 2010-10-19 10:27 ` Richard Weinberger 2010-10-18 19:22 ` [uml-devel] " Geert Uytterhoeven 2010-10-18 19:31 ` Richard Weinberger 2010-10-18 19:43 ` Geert Uytterhoeven 2010-10-18 20:03 ` Richard Weinberger
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