Commit Graph

51810 Commits

Author SHA1 Message Date
Long Li c739858334 CIFS: SMBD: Implement RDMA memory registration
Memory registration is used for transferring payload via RDMA read or write.
After I/O is done, memory registrations are recovered and reused. This
process can be time consuming and is done in a work queue.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2018-01-24 19:49:06 -06:00
Long Li 9762c2d080 CIFS: SMBD: Upper layer sends data via RDMA send
With SMB Direct connected, use it for sending data via RDMA send.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Long Li d649e1bba3 CIFS: SMBD: Implement function to send data via RDMA send
The transport doesn't maintain send buffers or send queue for transferring
payload via RDMA send. There is no data copy in the transport on send.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Long Li 2fef137a2e CIFS: SMBD: Upper layer receives data via RDMA receive
With SMB Direct connected, use it for receiving data via RDMA receive.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Long Li f64b78fd18 CIFS: SMBD: Implement function to receive data via RDMA receive
On the receive path, the transport maintains receive buffers and a reassembly
queue for transferring payload via RDMA recv. There is data copy in the
transport on recv when it copies the payload to upper layer.

The transport recognizes the RFC1002 header length use in the SMB
upper layer payloads in CIFS. Because this length is mainly used for TCP and
not applicable to RDMA, it is handled as a out-of-band information and is
never sent over the wire, and the trasnport behaves like TCP to upper layer
by processing and exposing the length correctly on data payloads.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Long Li 09902f8dc8 CIFS: SMBD: Set SMB Direct maximum read or write size for I/O
When connecting over SMB Direct, the transport negotiates its maximum I/O sizes
with the server and determines how to choose to do RDMA send/recv vs
read/write. Expose these maximum I/O sizes to upper layer so we will get the
correct sized payloads.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Long Li bce9ce7cc0 CIFS: SMBD: Upper layer destroys SMB Direct session on shutdown or umount
When upper layer wants to umount, make it call shutdown on transport when
SMB Direct is used.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Long Li 8ef130f9ec CIFS: SMBD: Implement function to destroy a SMB Direct connection
Add function to tear down a SMB Direct connection. This is used by upper layer
to free all SMB Direct connection and transport resources.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Long Li 781a8050f2 CIFS: SMBD: Upper layer reconnects to SMB Direct session
Do a reconnect on SMB Direct when it is used as the connection. Reconnect can
happen for many reasons and it's mostly the decision of SMB2 upper layer.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:06 -06:00
Long Li ad57b8e172 CIFS: SMBD: Implement function to reconnect to a SMB Direct transport
Add function to implement a reconnect to SMB Direct. This involves tearing down
the current connection and establishing/negotiating a new connection.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Long Li 2f8946464b CIFS: SMBD: Upper layer connects to SMBDirect session
When "rdma" is specified in the mount option, make CIFS connect to
SMB Direct.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-01-24 19:49:06 -06:00
Randy Dunlap 0933d6fa74 cifs: fix build errors for SMB_DIRECT
Prevent build errors when CIFS=y and INFINIBAND=m.

fs/cifs/smbdirect.o: In function `smbd_qp_async_error_upcall':
smbdirect.c:(.text+0x28c): undefined reference to `ib_event_msg'
fs/cifs/smbdirect.o: In function `smbd_destroy_rdma_work':
smbdirect.c:(.text+0xfde): undefined reference to `ib_drain_qp'
smbdirect.c:(.text+0xfea): undefined reference to `rdma_destroy_qp'
smbdirect.c:(.text+0x12a0): undefined reference to `ib_free_cq'
smbdirect.c:(.text+0x12ac): undefined reference to `ib_free_cq'
smbdirect.c:(.text+0x12b8): undefined reference to `ib_dealloc_pd'
smbdirect.c:(.text+0x12c4): undefined reference to `rdma_destroy_id'
fs/cifs/smbdirect.o: In function `_smbd_get_connection':
smbdirect.c:(.text+0x168c): undefined reference to `rdma_create_id'
smbdirect.c:(.text+0x1713): undefined reference to `rdma_resolve_addr'
smbdirect.c:(.text+0x1780): undefined reference to `rdma_resolve_route'
smbdirect.c:(.text+0x17e3): undefined reference to `rdma_destroy_id'
smbdirect.c:(.text+0x183d): undefined reference to `rdma_destroy_id'
smbdirect.c:(.text+0x199d): undefined reference to `ib_alloc_cq'
smbdirect.c:(.text+0x19d9): undefined reference to `ib_alloc_cq'
smbdirect.c:(.text+0x1a89): undefined reference to `rdma_create_qp'
smbdirect.c:(.text+0x1b3c): undefined reference to `rdma_connect'
smbdirect.c:(.text+0x2538): undefined reference to `rdma_destroy_qp'
smbdirect.c:(.text+0x2549): undefined reference to `ib_free_cq'
smbdirect.c:(.text+0x255a): undefined reference to `ib_free_cq'
smbdirect.c:(.text+0x2563): undefined reference to `ib_dealloc_pd'
smbdirect.c:(.text+0x256c): undefined reference to `rdma_destroy_id'
smbdirect.c:(.text+0x25f0): undefined reference to `__ib_alloc_pd'
smbdirect.c:(.text+0x26bb): undefined reference to `rdma_disconnect'
fs/cifs/smbdirect.o: In function `smbd_disconnect_rdma_work':
smbdirect.c:(.text+0x62): undefined reference to `rdma_disconnect'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc:	Steve French <sfrench@samba.org>
Cc:	linux-cifs@vger.kernel.org
Cc:	samba-technical@lists.samba.org (moderated for non-subscribers)
Signed-off-by: Steve French <smfrench@gmail.com>
2018-01-24 19:49:06 -06:00
Matthew Wilcox f04a703c3d cifs: Fix missing put_xid in cifs_file_strict_mmap
If cifs_zap_mapping() returned an error, we would return without putting
the xid that we got earlier.  Restructure cifs_file_strict_mmap() and
cifs_file_mmap() to be more similar to each other and have a single
point of return that always puts the xid.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
CC: Stable <stable@vger.kernel.org>
2018-01-24 19:49:06 -06:00
Long Li d8ec913b17 CIFS: SMBD: export protocol initial values
For use-configurable SMB Direct protocol values, export them to /proc/fs/cifs.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:06 -06:00
Long Li 399f9539d9 CIFS: SMBD: Implement function to create a SMB Direct connection
The upper layer calls this function to connect to peer through SMB Direct.
Each SMB Direct connection is based on a RDMA RC Queue Pair.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:05 -06:00
Long Li f198186aa9 CIFS: SMBD: Establish SMB Direct connection
Add code to implement the core functions to establish a SMB Direct connection.

1. Establish an RDMA connection to SMB server.
2. Negotiate and setup SMB Direct protocol.
3. Implement idle connection timer and credit management.

SMB Direct is enabled by setting CONFIG_CIFS_SMB_DIRECT.

Add to Makefile to enable building SMB Direct.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:05 -06:00
Long Li 03bee01d62 CIFS: SMBD: Add SMB Direct protocol initial values and constants
To prepare for protocol implementation, add constants and user-configurable
values for the SMB Direct protocol.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Ronnie Sahlberg <lsahlber.redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:05 -06:00
Long Li 8339dd32fb CIFS: SMBD: Add rdma mount option
Add "rdma" to CIFS mount options to connect to SMB Direct.
Add checks to validate this is used on SMB 3.X dialects.

To connect to SMBDirect, use "mount.cifs -o rdma,vers=3.x".
At the time of this patch, 3.x can be 3.0, 3.02 or 3.1.1.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Ronnie Sahlberg <lsahlber.redhat.com>
2018-01-24 19:49:05 -06:00
Long Li 2b6ed88037 CIFS: SMBD: Introduce kernel config option CONFIG_CIFS_SMB_DIRECT
Build SMB Direct code when this option is set.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Ronnie Sahlberg <lsahlber.redhat.com>
2018-01-24 19:49:05 -06:00
Long Li 2dabfd5bab CIFS: SMBD: Add parameter rdata to smb2_new_read_req
This patch is for preparing upper layer for doing SMB read via RDMA write.

When we assemble the SMB read packet header, we need to know the I/O layout
if this request is to use a RDMA write. rdata has all the information we need
for memory registration. Add rdata to smb2_new_read_req.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Ronnie Sahlberg <lsahlber.redhat.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg 3cecf4865c cifs: avoid a kmalloc in smb2_send_recv/SendReceive2 for the common case
In both functions, use an array of 8 (arbitrary but should be big enough
for all current uses) iov and avoid having to kmalloc the array
for the common case.

If 8 is too small, then fall back to the original behaviour and use
kmalloc/kfree.

This should not change any behaviour but should save us a tiny amount of
cpu cycles.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg 305428acf0 cifs: remove small_smb2_init
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg 8eb7998e79 cifs: remove rfc1002 header from smb2_lease_ack
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg 5dfe69a407 cifs: remove unused variable from SMB2_read
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg 21ad9487ca cifs: remove rfc1002 header from smb2_oplock_break we get from server
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg b2fb7fecc9 cifs: remove rfc1002 header from smb2_query_info_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg 7c00c3a625 cifs: remove rfc1002 header from smb2_query_directory_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg 2fc803efe6 cifs: remove rfc1002 header from smb2_set_info_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-01-24 19:49:05 -06:00
Ronnie Sahlberg f5688a6d7c cifs: remove rfc1002 header from smb2 read/write requests
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg ced93679cb cifs: remove rfc1002 header from smb2_lock_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 1f444e4c06 cifs: remove rfc1002 header from smb2_flush_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 4f33bc3587 cifs: remove rfc1002 header from smb2_create_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 88ea5cb7d4 cifs: remove rfc1002 header from smb2_sess_setup_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 661bb943a9 cifs: remove rfc1002 header from smb2_tree_connect_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 7f7ae759fb cifs: remove rfc1002 header from smb2_echo_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 9775468020 cifs: remove rfc1002 header from smb2_ioctl_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg afcccefdc3 cifs: remove rfc1002 header from smb2_close_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 4eecf4cfe1 cifs: remove rfc1002 header from smb2_tree_disconnect_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 45305eda6b cifs: remove rfc1002 header from smb2_logoff_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 13cacea7bb cifs: remove rfc1002 header from smb2_negotiate_req
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2018-01-24 19:49:04 -06:00
Ronnie Sahlberg 83b7739180 cifs: Add smb2_send_recv
This function is similar to SendReceive2 except it does not expect
a 4 byte rfc1002 length header in the first io vector.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2018-01-24 19:49:04 -06:00
Ben Hutchings 1995266727 nfsd: auth: Fix gid sorting when rootsquash enabled
Commit bdcf0a423e ("kernel: make groups_sort calling a responsibility
group_info allocators") appears to break nfsd rootsquash in a pretty
major way.

It adds a call to groups_sort() inside the loop that copies/squashes
gids, which means the valid gids are sorted along with the following
garbage.  The net result is that the highest numbered valid gids are
replaced with any lower-valued garbage gids, possibly including 0.

We should sort only once, after filling in all the gids.

Fixes: bdcf0a423e ("kernel: make groups_sort calling a responsibility ...")
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-22 20:13:07 -08:00
Martin Brandenburg a0ec1ded22 orangefs: initialize op on loop restart in orangefs_devreq_read
In orangefs_devreq_read, there is a loop which picks an op off the list
of pending ops.  If the loop fails to find an op, there is nothing to
read, and it returns EAGAIN.  If the op has been given up on, the loop
is restarted via a goto.  The bug is that the variable which the found
op is written to is not reinitialized, so if there are no more eligible
ops on the list, the code runs again on the already handled op.

This is triggered by interrupting a process while the op is being copied
to the client-core.  It's a fairly small window, but it's there.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-22 13:51:14 -08:00
Martin Brandenburg 0afc0decf2 orangefs: use list_for_each_entry_safe in purge_waiting_ops
set_op_state_purged can delete the op.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-22 13:51:14 -08:00
Alexey Dobriyan 8bb2ee192e proc: fix coredump vs read /proc/*/stat race
do_task_stat() accesses IP and SP of a task without bumping reference
count of a stack (which became an entity with independent lifetime at
some point).

Steps to reproduce:

    #include <stdio.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <sys/time.h>
    #include <sys/resource.h>
    #include <unistd.h>
    #include <sys/wait.h>

    int main(void)
    {
    	setrlimit(RLIMIT_CORE, &(struct rlimit){});

    	while (1) {
    		char buf[64];
    		char buf2[4096];
    		pid_t pid;
    		int fd;

    		pid = fork();
    		if (pid == 0) {
    			*(volatile int *)0 = 0;
    		}

    		snprintf(buf, sizeof(buf), "/proc/%u/stat", pid);
    		fd = open(buf, O_RDONLY);
    		read(fd, buf2, sizeof(buf2));
    		close(fd);

    		waitpid(pid, NULL, 0);
    	}
    	return 0;
    }

    BUG: unable to handle kernel paging request at 0000000000003fd8
    IP: do_task_stat+0x8b4/0xaf0
    PGD 800000003d73e067 P4D 800000003d73e067 PUD 3d558067 PMD 0
    Oops: 0000 [#1] PREEMPT SMP PTI
    CPU: 0 PID: 1417 Comm: a.out Not tainted 4.15.0-rc8-dirty #2
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc27 04/01/2014
    RIP: 0010:do_task_stat+0x8b4/0xaf0
    Call Trace:
     proc_single_show+0x43/0x70
     seq_read+0xe6/0x3b0
     __vfs_read+0x1e/0x120
     vfs_read+0x84/0x110
     SyS_read+0x3d/0xa0
     entry_SYSCALL_64_fastpath+0x13/0x6c
    RIP: 0033:0x7f4d7928cba0
    RSP: 002b:00007ffddb245158 EFLAGS: 00000246
    Code: 03 b7 a0 01 00 00 4c 8b 4c 24 70 4c 8b 44 24 78 4c 89 74 24 18 e9 91 f9 ff ff f6 45 4d 02 0f 84 fd f7 ff ff 48 8b 45 40 48 89 ef <48> 8b 80 d8 3f 00 00 48 89 44 24 20 e8 9b 97 eb ff 48 89 44 24
    RIP: do_task_stat+0x8b4/0xaf0 RSP: ffffc90000607cc8
    CR2: 0000000000003fd8

John Ogness said: for my tests I added an else case to verify that the
race is hit and correctly mitigated.

Link: http://lkml.kernel.org/r/20180116175054.GA11513@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reported-by: "Kohli, Gaurav" <gkohli@codeaurora.org>
Tested-by: John Ogness <john.ogness@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-19 10:09:41 -08:00
Linus Torvalds 75d4276e83 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:

 - untangle sys_close() abuses in xt_bpf

 - deal with register_shrinker() failures in sget()

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fix "netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1'"
  sget(): handle failures of register_shrinker()
  mm,vmscan: Make unregister_shrinker() no-op if register_shrinker() failed.
2018-01-06 17:13:21 -08:00
Linus Torvalds 89876f275e for-4.15-rc7-tag
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Merge tag 'for-4.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "We have two more fixes for 4.15, both aimed for stable.

  The leak fix is obvious, the second patch fixes a bug revealed by the
  refcount API, when it behaves differently than previous atomic_t and
  reports refs going from 0 to 1 in one case"

* tag 'for-4.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix refcount_t usage when deleting btrfs_delayed_nodes
  btrfs: Fix flush bio leak
2018-01-05 13:02:46 -08:00
Linus Torvalds 12e971b652 Changes since last update:
- Fix resource cleanup of failed quota initialization
 - Fix integer overflow problems wrt s_maxbytes
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Merge tag 'xfs-4.15-fixes-10' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull XFS fixes from Darrick Wong:
 "I have just a few fixes for bugs and resource cleanup problems this
  week:

   - Fix resource cleanup of failed quota initialization

   - Fix integer overflow problems wrt s_maxbytes"

* tag 'xfs-4.15-fixes-10' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: fix s_maxbytes overflow problems
  xfs: quota: check result of register_shrinker()
  xfs: quota: fix missed destroy of qi_tree_lock
2018-01-05 12:59:32 -08:00
Andrea Arcangeli 0cbb4b4f4c userfaultfd: clear the vma->vm_userfaultfd_ctx if UFFD_EVENT_FORK fails
The previous fix in commit 384632e67e ("userfaultfd: non-cooperative:
fix fork use after free") corrected the refcounting in case of
UFFD_EVENT_FORK failure for the fork userfault paths.

That still didn't clear the vma->vm_userfaultfd_ctx of the vmas that
were set to point to the aborted new uffd ctx earlier in
dup_userfaultfd.

Link: http://lkml.kernel.org/r/20171223002505.593-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-04 16:45:09 -08:00
Linus Torvalds 50d0f78f5c Merge branch 'afs-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull afs/fscache fixes from David Howells:

 - Fix the default return of fscache_maybe_release_page() when a cache
   isn't in use - it prevents a filesystem from releasing pages. This
   can cause a system to OOM.

 - Fix a potential uninitialised variable in AFS.

 - Fix AFS unlink's handling of the nlink count. It needs to use the
   nlink manipulation functions so that inode structs of deleted inodes
   actually get scheduled for destruction.

 - Fix error handling in afs_write_end() so that the page gets unlocked
   and put if we can't fill the unwritten portion.

* 'afs-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix missing error handling in afs_write_end()
  afs: Fix unlink
  afs: Potential uninitialized variable in afs_extract_data()
  fscache: Fix the default for fscache_maybe_release_page()
2018-01-03 10:58:56 -08:00