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linux/fs/cifs
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Dave Wysochanski d46b0da7a3 cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs 
There's a deadlock that is possible and can easily be seen with
a test where multiple readers open/read/close of the same file
and a disruption occurs causing reconnect.  The deadlock is due
a reader thread inside cifs_strict_readv calling down_read and
obtaining lock_sem, and then after reconnect inside
cifs_reopen_file calling down_read a second time.  If in
between the two down_read calls, a down_write comes from
another process, deadlock occurs.

        CPU0                    CPU1
        ----                    ----
cifs_strict_readv()
 down_read(&cifsi->lock_sem);
                               _cifsFileInfo_put
                                  OR
                               cifs_new_fileinfo
                                down_write(&cifsi->lock_sem);
cifs_reopen_file()
 down_read(&cifsi->lock_sem);

Fix the above by changing all down_write(lock_sem) calls to
down_write_trylock(lock_sem)/msleep() loop, which in turn
makes the second down_read call benign since it will never
block behind the writer while holding lock_sem.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed--by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
 		2019-10-24 21:35:04 -05:00
..
Kconfig various cifs/smb3 fixes (including for share deleted cases) and features including improved encrypted read performance, and various debugging improvements 2019-09-19 10:32:16 -07:00
Makefile cifs: Add support for root file systems 2019-09-16 11:43:38 -05:00
asn1.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
cache.c cifs: use 64-bit timestamps for fscache 2018-08-07 14:15:41 -05:00
cifs_debug.c smb3: display max smb3 requests in flight at any one time 2019-09-16 11:43:38 -05:00
cifs_debug.h cifs: add a debug macro that prints \\server\share for errors 2019-09-16 11:43:38 -05:00
cifs_dfs_ref.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cifs_fs_sb.h smb3: add mount option to allow RW caching of share accessed by only 1 client 2019-09-16 11:43:38 -05:00
cifs_ioctl.h smb3: allow decryption keys to be dumped by admin for debugging 2019-09-21 06:02:26 -05:00
cifs_spnego.c Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
cifs_spnego.h
…
cifs_unicode.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
cifs_unicode.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
cifs_uniupr.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
cifsacl.c cifs: modefromsid: write mode ACE first 2019-09-16 18:49:11 -05:00
cifsacl.h smb3: missing ACL related flags 2019-09-26 16:37:43 -05:00
cifsencrypt.c fs: cifs: switch to RC4 library interface 2019-06-20 14:19:55 +08:00
cifsfs.c cifs: clarify comment about timestamp granularity for old servers 2019-10-20 19:19:49 -05:00
cifsfs.h cifs: update internal module version number 2019-09-16 19:18:39 -05:00
cifsglob.h cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs 2019-10-24 21:35:04 -05:00
cifspdu.h smb3: missing defines and structs for reparse point handling 2018-11-02 14:09:41 -05:00
cifsproto.h cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs 2019-10-24 21:35:04 -05:00
cifsroot.c cifs: cifsroot: add more err checking 2019-09-16 11:43:39 -05:00
cifssmb.c smb3: pass mode bits into create calls 2019-09-26 02:06:42 -05:00
connect.c CIFS: Fix retry mid list corruption on reconnects 2019-10-24 21:32:32 -05:00
dfs_cache.c fs: cifs: Drop unlikely before IS_ERR(_OR_NULL) 2019-07-07 22:37:42 -05:00
dfs_cache.h cifs: Fix DFS cache refresher for DFS links 2019-05-07 23:24:54 -05:00
dir.c CIFS: Force reval dentry if LOOKUP_REVAL flag is set 2019-10-09 00:10:50 -05:00
dns_resolve.c keys: Pass the network namespace into request_key mechanism 2019-06-27 23:02:12 +01:00
dns_resolve.h
…
export.c docs: fs: convert docs without extension to ReST 2019-07-31 13:31:05 -06:00
file.c cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs 2019-10-24 21:35:04 -05:00
fscache.c cifs: use 64-bit timestamps for fscache 2018-08-07 14:15:41 -05:00
fscache.h cifs: use 64-bit timestamps for fscache 2018-08-07 14:15:41 -05:00
inode.c cifs: Fix missed free operations 2019-10-20 19:19:49 -05:00
ioctl.c smb3: allow decryption keys to be dumped by admin for debugging 2019-09-21 06:02:26 -05:00
link.c SMB3: Clean up query symlink when reparse point 2019-05-07 23:24:55 -05:00
misc.c cifs: replace various strncpy with strscpy and similar 2019-08-27 17:25:12 -05:00
netmisc.c fs: cifs: mute -Wunused-const-variable message 2019-10-06 22:04:35 -05:00
nterr.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
nterr.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
ntlmssp.h
…
readdir.c cifs: check ntwrk_buf_start for NULL before dereferencing it 2018-12-23 22:41:31 -06:00
rfc1002pdu.h
…
sess.c fs/cifs/sess.c: Remove set but not used variable 'capabilities' 2019-09-23 22:51:57 -05:00
smb1ops.c CIFS: avoid using MID 0xFFFF 2019-10-20 19:19:49 -05:00
smb2file.c cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs 2019-10-24 21:35:04 -05:00
smb2glob.h cifs: change SMB2_OP_RENAME and SMB2_OP_HARDLINK to use compounding 2018-10-23 21:16:04 -05:00
smb2inode.c smb3: pass mode bits into create calls 2019-09-26 02:06:42 -05:00
smb2maperror.c smb3: improve handling of share deleted (and share recreated) 2019-09-16 11:43:38 -05:00
smb2misc.c CIFS: keep FileInfo handle live during oplock break 2019-04-16 09:38:38 -05:00
smb2ops.c CIFS: Fix oplock handling for SMB 2.1+ protocols 2019-09-26 16:42:44 -05:00
smb2pdu.c smb3: remove noisy debug message and minor cleanup 2019-10-08 18:19:40 -07:00
smb2pdu.h smb3: add missing flag definitions 2019-09-16 11:43:37 -05:00
smb2proto.h smb3: cleanup some recent endian errors spotted by updated sparse 2019-10-06 22:04:29 -05:00
smb2status.h cifs: don't use __constant_cpu_to_le32() 2019-05-07 23:24:54 -05:00
smb2transport.c smb3: allow skipping signature verification for perf sensitive configurations 2019-09-16 11:43:38 -05:00
smbdirect.c rdma: Enable ib_alloc_cq to spread work over a device's comp_vectors 2019-08-05 11:50:32 -04:00
smbdirect.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
smbencrypt.c fs: cifs: move from the crypto cipher API to the new DES library interface 2019-08-22 14:57:34 +10:00
smberr.h
…
smbfsctl.h smb3: Add missing reparse tags 2019-09-24 23:31:32 -05:00
trace.c smb3: Cleanup license mess 2019-01-24 09:37:33 -06:00
trace.h smb3: add missing worker function for SMB3 change notify 2019-09-16 11:43:39 -05:00
transport.c CIFS: Fix retry mid list corruption on reconnects 2019-10-24 21:32:32 -05:00
winucase.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
xattr.c CIFS: fix max ea value size 2019-09-23 23:28:59 -05:00