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author | Baokun Li <libaokun1@huawei.com> | 2024-05-22 14:43:07 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-06-21 15:40:16 +0300 |
commit | e73fac95084839c5178d97e81c6a2051251bdc00 (patch) | |
tree | 33225fbda1d0a194e7d6a1e05ad25ba07db031e3 /fs/cachefiles/daemon.c | |
parent | b9f58cdae6a364a3270fd6b6a46e0fd4f7f8ce32 (diff) | |
download | linux-e73fac95084839c5178d97e81c6a2051251bdc00.tar.xz |
cachefiles: flush all requests after setting CACHEFILES_DEAD
[ Upstream commit 85e833cd7243bda7285492b0653c3abb1e2e757b ]
In ondemand mode, when the daemon is processing an open request, if the
kernel flags the cache as CACHEFILES_DEAD, the cachefiles_daemon_write()
will always return -EIO, so the daemon can't pass the copen to the kernel.
Then the kernel process that is waiting for the copen triggers a hung_task.
Since the DEAD state is irreversible, it can only be exited by closing
/dev/cachefiles. Therefore, after calling cachefiles_io_error() to mark
the cache as CACHEFILES_DEAD, if in ondemand mode, flush all requests to
avoid the above hungtask. We may still be able to read some of the cached
data before closing the fd of /dev/cachefiles.
Note that this relies on the patch that adds reference counting to the req,
otherwise it may UAF.
Fixes: c8383054506c ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240522114308.2402121-12-libaokun@huaweicloud.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/cachefiles/daemon.c')
-rw-r--r-- | fs/cachefiles/daemon.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index ccb7b707ea4b..06cdf1a8a16f 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -133,7 +133,7 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file) return 0; } -static void cachefiles_flush_reqs(struct cachefiles_cache *cache) +void cachefiles_flush_reqs(struct cachefiles_cache *cache) { struct xarray *xa = &cache->reqs; struct cachefiles_req *req; |