Message ID | 1493824641-9455-1-git-send-email-rabin.vincent@axis.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
2017-05-03 8:17 GMT-07:00 Rabin Vincent <rabin.vincent@axis.com>: > From: Rabin Vincent <rabinv@axis.com> > > cifs_relock_file() can perform a down_write() on the inode's lock_sem even > though it was already performed in cifs_strict_readv(). Lockdep complains > about this. AFAICS, there is no problem here, and lockdep just needs to be > told that this nesting is OK. > > ============================================= > [ INFO: possible recursive locking detected ] > 4.11.0+ #20 Not tainted > --------------------------------------------- > cat/701 is trying to acquire lock: > (&cifsi->lock_sem){++++.+}, at: cifs_reopen_file+0x7a7/0xc00 > > but task is already holding lock: > (&cifsi->lock_sem){++++.+}, at: cifs_strict_readv+0x177/0x310 > > other info that might help us debug this: > Possible unsafe locking scenario: > > CPU0 > ---- > lock(&cifsi->lock_sem); > lock(&cifsi->lock_sem); > > *** DEADLOCK *** > > May be due to missing lock nesting notation > > 1 lock held by cat/701: > #0: (&cifsi->lock_sem){++++.+}, at: cifs_strict_readv+0x177/0x310 > > stack backtrace: > CPU: 0 PID: 701 Comm: cat Not tainted 4.11.0+ #20 > Call Trace: > dump_stack+0x85/0xc2 > __lock_acquire+0x17dd/0x2260 > ? trace_hardirqs_on_thunk+0x1a/0x1c > ? preempt_schedule_irq+0x6b/0x80 > lock_acquire+0xcc/0x260 > ? lock_acquire+0xcc/0x260 > ? cifs_reopen_file+0x7a7/0xc00 > down_read+0x2d/0x70 > ? cifs_reopen_file+0x7a7/0xc00 > cifs_reopen_file+0x7a7/0xc00 > ? printk+0x43/0x4b > cifs_readpage_worker+0x327/0x8a0 > cifs_readpage+0x8c/0x2a0 > generic_file_read_iter+0x692/0xd00 > cifs_strict_readv+0x29f/0x310 > generic_file_splice_read+0x11c/0x1c0 > do_splice_to+0xa5/0xc0 > splice_direct_to_actor+0xfa/0x350 > ? generic_pipe_buf_nosteal+0x10/0x10 > do_splice_direct+0xb5/0xe0 > do_sendfile+0x278/0x3a0 > SyS_sendfile64+0xc4/0xe0 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > Signed-off-by: Rabin Vincent <rabinv@axis.com> > --- > fs/cifs/file.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/cifs/file.c b/fs/cifs/file.c > index 21d4045..64b590b 100644 > --- a/fs/cifs/file.c > +++ b/fs/cifs/file.c > @@ -582,7 +582,7 @@ cifs_relock_file(struct cifsFileInfo *cfile) > struct cifs_tcon *tcon = tlink_tcon(cfile->tlink); > int rc = 0; > > - down_read(&cinode->lock_sem); > + down_read_nested(&cinode->lock_sem, SINGLE_DEPTH_NESTING); > if (cinode->can_cache_brlcks) { > /* can cache locks - no need to relock */ > up_read(&cinode->lock_sem); > -- > 2.1.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-cifs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Best regards, Pavel Shilovsky -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
merged into cifs-2.6.git for-next thx On Tue, May 9, 2017 at 8:34 PM, Pavel Shilovsky <pshilovsky@samba.org> wrote: > 2017-05-03 8:17 GMT-07:00 Rabin Vincent <rabin.vincent@axis.com>: >> From: Rabin Vincent <rabinv@axis.com> >> >> cifs_relock_file() can perform a down_write() on the inode's lock_sem even >> though it was already performed in cifs_strict_readv(). Lockdep complains >> about this. AFAICS, there is no problem here, and lockdep just needs to be >> told that this nesting is OK. >> >> ============================================= >> [ INFO: possible recursive locking detected ] >> 4.11.0+ #20 Not tainted >> --------------------------------------------- >> cat/701 is trying to acquire lock: >> (&cifsi->lock_sem){++++.+}, at: cifs_reopen_file+0x7a7/0xc00 >> >> but task is already holding lock: >> (&cifsi->lock_sem){++++.+}, at: cifs_strict_readv+0x177/0x310 >> >> other info that might help us debug this: >> Possible unsafe locking scenario: >> >> CPU0 >> ---- >> lock(&cifsi->lock_sem); >> lock(&cifsi->lock_sem); >> >> *** DEADLOCK *** >> >> May be due to missing lock nesting notation >> >> 1 lock held by cat/701: >> #0: (&cifsi->lock_sem){++++.+}, at: cifs_strict_readv+0x177/0x310 >> >> stack backtrace: >> CPU: 0 PID: 701 Comm: cat Not tainted 4.11.0+ #20 >> Call Trace: >> dump_stack+0x85/0xc2 >> __lock_acquire+0x17dd/0x2260 >> ? trace_hardirqs_on_thunk+0x1a/0x1c >> ? preempt_schedule_irq+0x6b/0x80 >> lock_acquire+0xcc/0x260 >> ? lock_acquire+0xcc/0x260 >> ? cifs_reopen_file+0x7a7/0xc00 >> down_read+0x2d/0x70 >> ? cifs_reopen_file+0x7a7/0xc00 >> cifs_reopen_file+0x7a7/0xc00 >> ? printk+0x43/0x4b >> cifs_readpage_worker+0x327/0x8a0 >> cifs_readpage+0x8c/0x2a0 >> generic_file_read_iter+0x692/0xd00 >> cifs_strict_readv+0x29f/0x310 >> generic_file_splice_read+0x11c/0x1c0 >> do_splice_to+0xa5/0xc0 >> splice_direct_to_actor+0xfa/0x350 >> ? generic_pipe_buf_nosteal+0x10/0x10 >> do_splice_direct+0xb5/0xe0 >> do_sendfile+0x278/0x3a0 >> SyS_sendfile64+0xc4/0xe0 >> entry_SYSCALL_64_fastpath+0x1f/0xbe >> >> Signed-off-by: Rabin Vincent <rabinv@axis.com> >> --- >> fs/cifs/file.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/cifs/file.c b/fs/cifs/file.c >> index 21d4045..64b590b 100644 >> --- a/fs/cifs/file.c >> +++ b/fs/cifs/file.c >> @@ -582,7 +582,7 @@ cifs_relock_file(struct cifsFileInfo *cfile) >> struct cifs_tcon *tcon = tlink_tcon(cfile->tlink); >> int rc = 0; >> >> - down_read(&cinode->lock_sem); >> + down_read_nested(&cinode->lock_sem, SINGLE_DEPTH_NESTING); >> if (cinode->can_cache_brlcks) { >> /* can cache locks - no need to relock */ >> up_read(&cinode->lock_sem); >> -- >> 2.1.4 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > Acked-by: Pavel Shilovsky <pshilov@microsoft.com> > > Best regards, > Pavel Shilovsky > -- > To unsubscribe from this list: send the line "unsubscribe linux-cifs" 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/cifs/file.c b/fs/cifs/file.c index 21d4045..64b590b 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -582,7 +582,7 @@ cifs_relock_file(struct cifsFileInfo *cfile) struct cifs_tcon *tcon = tlink_tcon(cfile->tlink); int rc = 0; - down_read(&cinode->lock_sem); + down_read_nested(&cinode->lock_sem, SINGLE_DEPTH_NESTING); if (cinode->can_cache_brlcks) { /* can cache locks - no need to relock */ up_read(&cinode->lock_sem);