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authorJan Niehusmann <jan@gondor.com>2006-05-15 09:44:12 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-05-15 11:20:56 -0700
commit48564e628bd7662d7a0b3ac81c41cd0e4cc36dae (patch)
tree44f5d76fb7dfa2636b790a0aea1fe8568807a088 /fs/smbfs
parent2e367a82fc2da335455984a7722c721dd3fa782b (diff)
downloadlinux-linaro-48564e628bd7662d7a0b3ac81c41cd0e4cc36dae.tar.gz
[PATCH] smbfs: Fix slab corruption in samba error path
Yesterday, I got the following error with 2.6.16.13 during a file copy from a smb filesystem over a wireless link. I guess there was some error on the wireless link, which in turn caused an error condition for the smb filesystem. In the log, smb_file_read reports error=4294966784 (0xfffffe00), which also shows up in the slab dumps, and also is -ERESTARTSYS. Error code 27499 corresponds to 0x6b6b, so the rq_errno field seems to be the only one being set after freeing the slab. In smb_add_request (which is the only place in smbfs where I found ERESTARTSYS), I found the following: if (!timeleft || signal_pending(current)) { /* * On timeout or on interrupt we want to try and remove the * request from the recvq/xmitq. */ smb_lock_server(server); if (!(req->rq_flags & SMB_REQ_RECEIVED)) { list_del_init(&req->rq_queue); smb_rput(req); } smb_unlock_server(server); } [...] if (signal_pending(current)) req->rq_errno = -ERESTARTSYS; I guess that some codepath like smbiod_flush() caused the request to be removed from the queue, and smb_rput(req) be called, without SMB_REQ_RECEIVED being set. This violates an asumption made by the quoted code. Then, the above code calls smb_rput(req) again, the req gets freed, and req->rq_errno = -ERESTARTSYS writes into the already freed slab. As list_del_init doesn't cause an error if called multiple times, that does cause the observed behaviour (freed slab with rq_errno=-ERESTARTSYS). If this observation is correct, the following patch should fix it. I wonder why the smb code uses list_del_init everywhere - using list_del instead would catch such situations by poisoning the next and prev pointers. May 4 23:29:21 knautsch kernel: [17180085.456000] ipw2200: Firmware error detected. Restarting. May 4 23:29:21 knautsch kernel: [17180085.456000] ipw2200: Sysfs 'error' log captured. May 4 23:33:02 knautsch kernel: [17180306.316000] ipw2200: Firmware error detected. Restarting. May 4 23:33:02 knautsch kernel: [17180306.316000] ipw2200: Sysfs 'error' log already exists. May 4 23:33:02 knautsch kernel: [17180306.968000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:34:18 knautsch kernel: [17180383.256000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:34:18 knautsch kernel: [17180383.284000] SMB connection re-established (-5) May 4 23:37:19 knautsch kernel: [17180563.956000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:40:09 knautsch kernel: [17180733.636000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:40:26 knautsch kernel: [17180750.700000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:43:02 knautsch kernel: [17180907.304000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:43:08 knautsch kernel: [17180912.324000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:43:34 knautsch kernel: [17180938.416000] smb_errno: class Unknown, code 27499 from command 0x6b May 4 23:43:34 knautsch kernel: [17180938.416000] Slab corruption: start=c4ebe09c, len=244 May 4 23:43:34 knautsch kernel: [17180938.416000] Redzone: 0x5a2cf071/0x5a2cf071. May 4 23:43:34 knautsch kernel: [17180938.416000] Last user: [<e087b903>](smb_rput+0x53/0x90 [smbfs]) May 4 23:43:34 knautsch kernel: [17180938.416000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b May 4 23:43:34 knautsch kernel: [17180938.416000] 0f0: 00 fe ff ff May 4 23:43:34 knautsch kernel: [17180938.416000] Next obj: start=c4ebe19c, len=244 May 4 23:43:34 knautsch kernel: [17180938.416000] Redzone: 0x5a2cf071/0x5a2cf071. May 4 23:43:34 knautsch kernel: [17180938.416000] Last user: [<00000000>](_stext+0x3feffde0/0x30) May 4 23:43:34 knautsch kernel: [17180938.416000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b May 4 23:43:34 knautsch kernel: [17180938.416000] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b May 4 23:43:34 knautsch kernel: [17180938.460000] SMB connection re-established (-5) May 4 23:43:42 knautsch kernel: [17180946.292000] ipw2200: Firmware error detected. Restarting. May 4 23:43:42 knautsch kernel: [17180946.292000] ipw2200: Sysfs 'error' log already exists. May 4 23:45:04 knautsch kernel: [17181028.752000] ipw2200: Firmware error detected. Restarting. May 4 23:45:04 knautsch kernel: [17181028.752000] ipw2200: Sysfs 'error' log already exists. May 4 23:45:05 knautsch kernel: [17181029.868000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:45:36 knautsch kernel: [17181060.984000] smb_errno: class Unknown, code 27499 from command 0x6b May 4 23:45:36 knautsch kernel: [17181060.984000] Slab corruption: start=c4ebe09c, len=244 May 4 23:45:36 knautsch kernel: [17181060.984000] Redzone: 0x5a2cf071/0x5a2cf071. May 4 23:45:36 knautsch kernel: [17181060.984000] Last user: [<e087b903>](smb_rput+0x53/0x90 [smbfs]) May 4 23:45:36 knautsch kernel: [17181060.984000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b May 4 23:45:36 knautsch kernel: [17181060.984000] 0f0: 00 fe ff ff May 4 23:45:36 knautsch kernel: [17181060.984000] Next obj: start=c4ebe19c, len=244 May 4 23:45:36 knautsch kernel: [17181060.984000] Redzone: 0x5a2cf071/0x5a2cf071. May 4 23:45:36 knautsch kernel: [17181060.984000] Last user: [<00000000>](_stext+0x3feffde0/0x30) May 4 23:45:36 knautsch kernel: [17181060.984000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b May 4 23:45:36 knautsch kernel: [17181060.984000] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b May 4 23:45:36 knautsch kernel: [17181061.024000] SMB connection re-established (-5) May 4 23:46:17 knautsch kernel: [17181102.132000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:47:46 knautsch kernel: [17181190.468000] smb_errno: class Unknown, code 27499 from command 0x6b May 4 23:47:46 knautsch kernel: [17181190.468000] Slab corruption: start=c4ebe09c, len=244 May 4 23:47:46 knautsch kernel: [17181190.468000] Redzone: 0x5a2cf071/0x5a2cf071. May 4 23:47:46 knautsch kernel: [17181190.468000] Last user: [<e087b903>](smb_rput+0x53/0x90 [smbfs]) May 4 23:47:46 knautsch kernel: [17181190.468000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b May 4 23:47:46 knautsch kernel: [17181190.468000] 0f0: 00 fe ff ff May 4 23:47:46 knautsch kernel: [17181190.468000] Next obj: start=c4ebe19c, len=244 May 4 23:47:46 knautsch kernel: [17181190.468000] Redzone: 0x5a2cf071/0x5a2cf071. May 4 23:47:46 knautsch kernel: [17181190.468000] Last user: [<00000000>](_stext+0x3feffde0/0x30) May 4 23:47:46 knautsch kernel: [17181190.468000] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b May 4 23:47:46 knautsch kernel: [17181190.468000] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b May 4 23:47:46 knautsch kernel: [17181190.492000] SMB connection re-established (-5) May 4 23:49:20 knautsch kernel: [17181284.828000] smb_file_read: //some_file validation failed, error=4294966784 May 4 23:49:39 knautsch kernel: [17181303.896000] smb_file_read: //some_file validation failed, error=4294966784 Signed-off-by: Jan Niehusmann <jan@gondor.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/smbfs')
-rw-r--r--fs/smbfs/request.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/smbfs/request.c b/fs/smbfs/request.c
index c71c375863c..c71dd2760d3 100644
--- a/fs/smbfs/request.c
+++ b/fs/smbfs/request.c
@@ -339,9 +339,11 @@ int smb_add_request(struct smb_request *req)
/*
* On timeout or on interrupt we want to try and remove the
* request from the recvq/xmitq.
+ * First check if the request is still part of a queue. (May
+ * have been removed by some error condition)
*/
smb_lock_server(server);
- if (!(req->rq_flags & SMB_REQ_RECEIVED)) {
+ if (!list_empty(&req->rq_queue)) {
list_del_init(&req->rq_queue);
smb_rput(req);
}