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[46.135.14.82]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-477625c2f90sm8914505e9.12.2025.11.05.13.20.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Nov 2025 13:20:38 -0800 (PST) From: Mateusz Guzik To: mic@digikod.net, brauner@kernel.org Cc: linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, eadavis@qq.com, gnoack@google.com, jack@suse.cz, jannh@google.com, max.kellermann@ionos.com, m@maowtm.org, syzbot+12479ae15958fc3f54ec@syzkaller.appspotmail.com, Mateusz Guzik Subject: [PATCH 2/2] landlock: fix splats from iput() after it started calling might_sleep() Date: Wed, 5 Nov 2025 22:20:25 +0100 Message-ID: <20251105212025.807549-2-mjguzik@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251105212025.807549-1-mjguzik@gmail.com> References: <20251105212025.807549-1-mjguzik@gmail.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit At this point it is guaranteed this is not the last reference. However, a recent addition of might_sleep() at top of iput() started generating false-positives as it was executing for all values. Remedy the problem by using the newly introduced iput_not_last(). Reported-by: syzbot+12479ae15958fc3f54ec@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68d32659.a70a0220.4f78.0012.GAE@google.com/ Fixes: 2ef435a872ab ("fs: add might_sleep() annotation to iput() and more") Signed-off-by: Mateusz Guzik --- security/landlock/fs.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 0bade2c5aa1d..d9c12b993fa7 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -1335,11 +1335,10 @@ static void hook_sb_delete(struct super_block *const sb) * At this point, we own the ihold() reference that was * originally set up by get_inode_object() and the * __iget() reference that we just set in this loop - * walk. Therefore the following call to iput() will - * not sleep nor drop the inode because there is now at - * least two references to it. + * walk. Therefore there are at least two references + * on the inode. */ - iput(inode); + iput_not_last(inode); } else { spin_unlock(&object->lock); rcu_read_unlock(); -- 2.48.1