From: Joel Fernandes <joel@joelfernandes.org> To: Phong Tran <tranmanphong@gmail.com> Cc: Jan Kara <jack@suse.cz>, "Theodore Y. Ts'o" <tytso@mit.edu>, adilger.kernel@dilger.ca, "Paul E. McKenney" <paulmck@kernel.org>, linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>, linux-kernel-mentees@lists.linuxfoundation.org, rcu <rcu@vger.kernel.org>, stable <stable@vger.kernel.org> Subject: Re: [PATCH V2] ext4: use rcu API in debug_print_tree Date: Fri, 13 Dec 2019 10:11:50 -0800 [thread overview] Message-ID: <CAEXW_YQwrM6=u1gsij-5SL5+2n9Pk9HFEYdF_JWYjitLvr7Dcg@mail.gmail.com> (raw) In-Reply-To: <20191213153306.30744-1-tranmanphong@gmail.com> On Fri, Dec 13, 2019 at 7:39 AM Phong Tran <tranmanphong@gmail.com> wrote: > > struct ext4_sb_info.system_blks was marked __rcu. > But access the pointer without using RCU lock and dereference. > Sparse warning with __rcu notation: > > block_validity.c:139:29: warning: incorrect type in argument 1 (different address spaces) > block_validity.c:139:29: expected struct rb_root const * > block_validity.c:139:29: got struct rb_root [noderef] <asn:4> * > > Reviewed-by: Jan Kara <jack@suse.cz> > Signed-off-by: Phong Tran <tranmanphong@gmail.com> Thanks Phong! Looks like a real bug fix caught thanks to Sparse. So let us mark for stable as well? - Joel > --- > fs/ext4/block_validity.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > --- > change log: > V2: Add Reviewed-by: Jan Kara <jack@suse.cz> > > diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c > index d4d4fdfac1a6..1ee04e76bbe0 100644 > --- a/fs/ext4/block_validity.c > +++ b/fs/ext4/block_validity.c > @@ -133,10 +133,13 @@ static void debug_print_tree(struct ext4_sb_info *sbi) > { > struct rb_node *node; > struct ext4_system_zone *entry; > + struct ext4_system_blocks *system_blks; > int first = 1; > > printk(KERN_INFO "System zones: "); > - node = rb_first(&sbi->system_blks->root); > + rcu_read_lock(); > + system_blks = rcu_dereference(sbi->system_blks); > + node = rb_first(&system_blks->root); > while (node) { > entry = rb_entry(node, struct ext4_system_zone, node); > printk(KERN_CONT "%s%llu-%llu", first ? "" : ", ", > @@ -144,6 +147,7 @@ static void debug_print_tree(struct ext4_sb_info *sbi) > first = 0; > node = rb_next(node); > } > + rcu_read_unlock(); > printk(KERN_CONT "\n"); > } > > -- > 2.20.1 >
WARNING: multiple messages have this Message-ID (diff)
From: Joel Fernandes <joel@joelfernandes.org> To: Phong Tran <tranmanphong@gmail.com> Cc: "Theodore Y. Ts'o" <tytso@mit.edu>, "Paul E. McKenney" <paulmck@kernel.org>, LKML <linux-kernel@vger.kernel.org>, stable <stable@vger.kernel.org>, rcu <rcu@vger.kernel.org>, adilger.kernel@dilger.ca, Jan Kara <jack@suse.cz>, linux-ext4@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [Linux-kernel-mentees] [PATCH V2] ext4: use rcu API in debug_print_tree Date: Fri, 13 Dec 2019 10:11:50 -0800 [thread overview] Message-ID: <CAEXW_YQwrM6=u1gsij-5SL5+2n9Pk9HFEYdF_JWYjitLvr7Dcg@mail.gmail.com> (raw) In-Reply-To: <20191213153306.30744-1-tranmanphong@gmail.com> On Fri, Dec 13, 2019 at 7:39 AM Phong Tran <tranmanphong@gmail.com> wrote: > > struct ext4_sb_info.system_blks was marked __rcu. > But access the pointer without using RCU lock and dereference. > Sparse warning with __rcu notation: > > block_validity.c:139:29: warning: incorrect type in argument 1 (different address spaces) > block_validity.c:139:29: expected struct rb_root const * > block_validity.c:139:29: got struct rb_root [noderef] <asn:4> * > > Reviewed-by: Jan Kara <jack@suse.cz> > Signed-off-by: Phong Tran <tranmanphong@gmail.com> Thanks Phong! Looks like a real bug fix caught thanks to Sparse. So let us mark for stable as well? - Joel > --- > fs/ext4/block_validity.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > --- > change log: > V2: Add Reviewed-by: Jan Kara <jack@suse.cz> > > diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c > index d4d4fdfac1a6..1ee04e76bbe0 100644 > --- a/fs/ext4/block_validity.c > +++ b/fs/ext4/block_validity.c > @@ -133,10 +133,13 @@ static void debug_print_tree(struct ext4_sb_info *sbi) > { > struct rb_node *node; > struct ext4_system_zone *entry; > + struct ext4_system_blocks *system_blks; > int first = 1; > > printk(KERN_INFO "System zones: "); > - node = rb_first(&sbi->system_blks->root); > + rcu_read_lock(); > + system_blks = rcu_dereference(sbi->system_blks); > + node = rb_first(&system_blks->root); > while (node) { > entry = rb_entry(node, struct ext4_system_zone, node); > printk(KERN_CONT "%s%llu-%llu", first ? "" : ", ", > @@ -144,6 +147,7 @@ static void debug_print_tree(struct ext4_sb_info *sbi) > first = 0; > node = rb_next(node); > } > + rcu_read_unlock(); > printk(KERN_CONT "\n"); > } > > -- > 2.20.1 > _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
next prev parent reply other threads:[~2019-12-13 20:40 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-12-01 3:51 [PATCH] ext4: use rcu API in debug_print_tree Phong Tran 2019-12-01 3:51 ` [Linux-kernel-mentees] " Phong Tran 2019-12-13 11:35 ` Jan Kara 2019-12-13 11:35 ` [Linux-kernel-mentees] " Jan Kara 2019-12-13 15:33 ` [PATCH V2] " Phong Tran 2019-12-13 15:33 ` [Linux-kernel-mentees] " Phong Tran 2019-12-13 18:11 ` Joel Fernandes [this message] 2019-12-13 18:11 ` Joel Fernandes 2019-12-13 19:49 ` Jan Kara 2019-12-13 19:49 ` [Linux-kernel-mentees] " Jan Kara 2019-12-13 23:19 ` Joel Fernandes 2019-12-13 23:19 ` [Linux-kernel-mentees] " Joel Fernandes 2019-12-16 2:41 ` Theodore Y. Ts'o 2019-12-16 2:41 ` [Linux-kernel-mentees] " Theodore Y. Ts'o
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