| Message ID | 513EC692.4090907@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> -----Original Message----- > From: linux-nfs-owner@vger.kernel.org [mailto:linux-nfs-owner@vger.kernel.org] On Behalf Of > fanchaoting > Sent: Tuesday, March 12, 2013 2:09 PM > To: Myklebust, Trond > Cc: linux-nfs@vger.kernel.org > Subject: [PATCH] pnfs-block: may be return NULL when find a extent > > maybe return NULL when find a extent, if we use it later, > it will cause oops. > ah, I would say it is intentional because the lookup cannot fail here. If we are committing an extent but cannot find it in client's extent cache, it certainly is a bug somewhere else. I remember there are other places like this in block layout code as well and we used to put a BUG_ON() there. But since we are using the pointer right away and crash on NULL pointer dereference anyway, it was suggested to remove these BUG_ON()s during code review. Are you fixing this because you saw a crash or because some static code analyzer complains? Thanks, Tao > Signed-off-by: fanchaoting<fanchaoting@cn.fujitsu.com> > --- > fs/nfs/blocklayout/extents.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c > index 9c3e117..131ea59 100644 > --- a/fs/nfs/blocklayout/extents.c > +++ b/fs/nfs/blocklayout/extents.c > @@ -762,6 +762,11 @@ set_to_rw(struct pnfs_block_layout *bl, u64 offset, u64 length) > > spin_lock(&bl->bl_ext_lock); > be = bl_find_get_extent_locked(bl, offset); > + if (!be) { > + spin_unlock(&bl->bl_ext_lock); > + goto out_nosplit; > + } > + > rv = be->be_f_offset + be->be_length; > if (be->be_state != PNFS_BLOCK_INVALID_DATA) { > spin_unlock(&bl->bl_ext_lock); > -- > 1.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
Peng, Tao ??: >> -----Original Message----- >> From: linux-nfs-owner@vger.kernel.org [mailto:linux-nfs-owner@vger.kernel.org] On Behalf Of >> fanchaoting >> Sent: Tuesday, March 12, 2013 2:09 PM >> To: Myklebust, Trond >> Cc: linux-nfs@vger.kernel.org >> Subject: [PATCH] pnfs-block: may be return NULL when find a extent >> >> maybe return NULL when find a extent, if we use it later, >> it will cause oops. >> > ah, I would say it is intentional because the lookup cannot fail here. If we are committing an extent but cannot find it in client's extent cache, it certainly is a bug somewhere else. I remember there are other places like this in block layout code as well and we used to put a BUG_ON() there. But since we are using the pointer right away and crash on NULL pointer dereference anyway, it was suggested to remove these BUG_ON()s during code review. > Get it , thanks for telling me it. > Are you fixing this because you saw a crash or because some static code analyzer complains? > > Thanks, > Tao > >> Signed-off-by: fanchaoting<fanchaoting@cn.fujitsu.com> >> --- >> fs/nfs/blocklayout/extents.c | 5 +++++ >> 1 files changed, 5 insertions(+), 0 deletions(-) >> >> diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c >> index 9c3e117..131ea59 100644 >> --- a/fs/nfs/blocklayout/extents.c >> +++ b/fs/nfs/blocklayout/extents.c >> @@ -762,6 +762,11 @@ set_to_rw(struct pnfs_block_layout *bl, u64 offset, u64 length) >> >> spin_lock(&bl->bl_ext_lock); >> be = bl_find_get_extent_locked(bl, offset); >> + if (!be) { >> + spin_unlock(&bl->bl_ext_lock); >> + goto out_nosplit; >> + } >> + >> rv = be->be_f_offset + be->be_length; >> if (be->be_state != PNFS_BLOCK_INVALID_DATA) { >> spin_unlock(&bl->bl_ext_lock); >> -- >> 1.7.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c index 9c3e117..131ea59 100644 --- a/fs/nfs/blocklayout/extents.c +++ b/fs/nfs/blocklayout/extents.c @@ -762,6 +762,11 @@ set_to_rw(struct pnfs_block_layout *bl, u64 offset, u64 length) spin_lock(&bl->bl_ext_lock); be = bl_find_get_extent_locked(bl, offset); + if (!be) { + spin_unlock(&bl->bl_ext_lock); + goto out_nosplit; + } + rv = be->be_f_offset + be->be_length; if (be->be_state != PNFS_BLOCK_INVALID_DATA) { spin_unlock(&bl->bl_ext_lock);
maybe return NULL when find a extent, if we use it later, it will cause oops. Signed-off-by: fanchaoting<fanchaoting@cn.fujitsu.com> --- fs/nfs/blocklayout/extents.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html