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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2007-10-14 01:38:33 +0200
committerPeter Zijlstra <a.p.zijlstra@chello.nl>2007-10-14 01:38:33 +0200
commit14358e6ddaed27499d7d366b3e65c3e46b39e1c4 (patch)
treede5a8919db855568577d0388fe30b5d7689e1f90 /arch
parentd475fd428ce77aa2a8bc650d230e17663a4f49c3 (diff)
lockdep: annotate dir vs file i_mutex
On Mon, 2007-09-24 at 22:13 -0400, Steven Rostedt wrote: > The circular lock seems to be this: > > #1: > > sys_mmap2: down_write(&mm->mmap_sem); > nfs_revalidate_mapping: mutex_lock(&inode->i_mutex); > > > #0: > > vfs_readdir: mutex_lock(&inode->i_mutex); > - during the readdir (filldir64), we take a user fault (missing page?) > and call do_page_fault - > do_page_fault: down_read(&mm->mmap_sem); > > > So it does indeed look like a circular locking. Now the question is, "is > this a bug?". Looking like the inode of #1 must be a file or something > else that you can mmap and the inode of #0 seems it must be a directory. > I would say "no". > > Now if you can readdir on a file or mmap a directory, then this could be > an issue. > > Otherwise, I'd love to see someone teach lockdep about this issue! ;-) Make a distinction between file and dir usage of i_mutex. The inode should be complete and unused at unlock_new_inode(), re-init i_mutex depending on its type. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Diffstat (limited to 'arch')
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