9a19bad70c
rxrpc_service_prealloc_one() doesn't set the socket pointer on any new call it preallocates, but does add it to the rxrpc net namespace call list. This, however, causes rxrpc_put_call() to oops when the call is discarded when the socket is closed. rxrpc_put_call() needs the socket to be able to reach the namespace so that it can use a lock held therein. Fix this by setting a call's socket pointer immediately before discarding it. This can be triggered by unloading the kafs module, resulting in an oops like the following: BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 IP: rxrpc_put_call+0x1e2/0x32d PGD 0 P4D 0 Oops: 0000 [#1] SMP Modules linked in: kafs(E-) CPU: 3 PID: 3037 Comm: rmmod Tainted: G E 4.12.0-fscache+ #213 Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 task: ffff8803fc92e2c0 task.stack: ffff8803fef74000 RIP: 0010:rxrpc_put_call+0x1e2/0x32d RSP: 0018:ffff8803fef77e08 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8803fab99ac0 RCX: 000000000000000f RDX: ffffffff81c50a40 RSI: 000000000000000c RDI: ffff8803fc92ea88 RBP: ffff8803fef77e30 R08: ffff8803fc87b941 R09: ffffffff82946d20 R10: ffff8803fef77d10 R11: 00000000000076fc R12: 0000000000000005 R13: ffff8803fab99c20 R14: 0000000000000001 R15: ffffffff816c6aee FS: 00007f915a059700(0000) GS:ffff88041fb80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000030 CR3: 00000003fef39000 CR4: 00000000001406e0 Call Trace: rxrpc_discard_prealloc+0x325/0x341 rxrpc_listen+0xf9/0x146 kernel_listen+0xb/0xd afs_close_socket+0x3e/0x173 [kafs] afs_exit+0x1f/0x57 [kafs] SyS_delete_module+0x10f/0x19a do_syscall_64+0x8a/0x149 entry_SYSCALL64_slow_path+0x25/0x25 Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.