linux/net/caif/caif_socket.c

1114 lines
26 KiB

netvm: prevent a stream-specific deadlock This patch series is based on top of "Swap-over-NBD without deadlocking v15" as it depends on the same reservation of PF_MEMALLOC reserves logic. When a user or administrator requires swap for their application, they create a swap partition and file, format it with mkswap and activate it with swapon. In diskless systems this is not an option so if swap if required then swapping over the network is considered. The two likely scenarios are when blade servers are used as part of a cluster where the form factor or maintenance costs do not allow the use of disks and thin clients. The Linux Terminal Server Project recommends the use of the Network Block Device (NBD) for swap but this is not always an option. There is no guarantee that the network attached storage (NAS) device is running Linux or supports NBD. However, it is likely that it supports NFS so there are users that want support for swapping over NFS despite any performance concern. Some distributions currently carry patches that support swapping over NFS but it would be preferable to support it in the mainline kernel. Patch 1 avoids a stream-specific deadlock that potentially affects TCP. Patch 2 is a small modification to SELinux to avoid using PFMEMALLOC reserves. Patch 3 adds three helpers for filesystems to handle swap cache pages. For example, page_file_mapping() returns page->mapping for file-backed pages and the address_space of the underlying swap file for swap cache pages. Patch 4 adds two address_space_operations to allow a filesystem to pin all metadata relevant to a swapfile in memory. Upon successful activation, the swapfile is marked SWP_FILE and the address space operation ->direct_IO is used for writing and ->readpage for reading in swap pages. Patch 5 notes that patch 3 is bolting filesystem-specific-swapfile-support onto the side and that the default handlers have different information to what is available to the filesystem. This patch refactors the code so that there are generic handlers for each of the new address_space operations. Patch 6 adds an API to allow a vector of kernel addresses to be translated to struct pages and pinned for IO. Patch 7 adds support for using highmem pages for swap by kmapping the pages before calling the direct_IO handler. Patch 8 updates NFS to use the helpers from patch 3 where necessary. Patch 9 avoids setting PF_private on PG_swapcache pages within NFS. Patch 10 implements the new swapfile-related address_space operations for NFS and teaches the direct IO handler how to manage kernel addresses. Patch 11 prevents page allocator recursions in NFS by using GFP_NOIO where appropriate. Patch 12 fixes a NULL pointer dereference that occurs when using swap-over-NFS. With the patches applied, it is possible to mount a swapfile that is on an NFS filesystem. Swap performance is not great with a swap stress test taking roughly twice as long to complete than if the swap device was backed by NBD. This patch: netvm: prevent a stream-specific deadlock It could happen that all !SOCK_MEMALLOC sockets have buffered so much data that we're over the global rmem limit. This will prevent SOCK_MEMALLOC buffers from receiving data, which will prevent userspace from running, which is needed to reduce the buffered data. Fix this by exempting the SOCK_MEMALLOC sockets from the rmem limit. Once this change it applied, it is important that sockets that set SOCK_MEMALLOC do not clear the flag until the socket is being torn down. If this happens, a warning is generated and the tokens reclaimed to avoid accounting errors until the bug is fixed. [davem@davemloft.net: Warning about clearing SOCK_MEMALLOC] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Rik van Riel <riel@redhat.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Neil Brown <neilb@suse.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-31 16:44:41 -07:00
net: Remove WARN_ON_ONCE(sk->sk_forward_alloc) from sk_stream_kill_queues(). Christoph Paasch reported that commit b5fc29233d28 ("inet6: Remove inet6_destroy_sock() in sk->sk_prot->destroy().") started triggering WARN_ON_ONCE(sk->sk_forward_alloc) in sk_stream_kill_queues(). [0 - 2] Also, we can reproduce it by a program in [3]. In the commit, we delay freeing ipv6_pinfo.pktoptions from sk->destroy() to sk->sk_destruct(), so sk->sk_forward_alloc is no longer zero in inet_csk_destroy_sock(). The same check has been in inet_sock_destruct() from at least v2.6, we can just remove the WARN_ON_ONCE(). However, among the users of sk_stream_kill_queues(), only CAIF is not calling inet_sock_destruct(). Thus, we add the same WARN_ON_ONCE() to caif_sock_destructor(). [0]: https://lore.kernel.org/netdev/39725AB4-88F1-41B3-B07F-949C5CAEFF4F@icloud.com/ [1]: https://github.com/multipath-tcp/mptcp_net-next/issues/341 [2]: WARNING: CPU: 0 PID: 3232 at net/core/stream.c:212 sk_stream_kill_queues+0x2f9/0x3e0 Modules linked in: CPU: 0 PID: 3232 Comm: syz-executor.0 Not tainted 6.2.0-rc5ab24eb4698afbe147b424149c529e2a43ec24eb5 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:sk_stream_kill_queues+0x2f9/0x3e0 Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e ec 00 00 00 8b ab 08 01 00 00 e9 60 ff ff ff e8 d0 5f b6 fe 0f 0b eb 97 e8 c7 5f b6 fe <0f> 0b eb a0 e8 be 5f b6 fe 0f 0b e9 6a fe ff ff e8 02 07 e3 fe e9 RSP: 0018:ffff88810570fc68 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888101f38f40 RSI: ffffffff8285e529 RDI: 0000000000000005 RBP: 0000000000000ce0 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000ce0 R11: 0000000000000001 R12: ffff8881009e9488 R13: ffffffff84af2cc0 R14: 0000000000000000 R15: ffff8881009e9458 FS: 00007f7fdfbd5800(0000) GS:ffff88811b600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32923000 CR3: 00000001062fc006 CR4: 0000000000170ef0 Call Trace: <TASK> inet_csk_destroy_sock+0x1a1/0x320 __tcp_close+0xab6/0xe90 tcp_close+0x30/0xc0 inet_release+0xe9/0x1f0 inet6_release+0x4c/0x70 __sock_release+0xd2/0x280 sock_close+0x15/0x20 __fput+0x252/0xa20 task_work_run+0x169/0x250 exit_to_user_mode_prepare+0x113/0x120 syscall_exit_to_user_mode+0x1d/0x40 do_syscall_64+0x48/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc RIP: 0033:0x7f7fdf7ae28d Code: c1 20 00 00 75 10 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ee fb ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 37 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00000000007dfbb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f7fdf7ae28d RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000003 RBP: 0000000000000000 R08: 000000007f338e0f R09: 0000000000000e0f R10: 000000007f338e13 R11: 0000000000000293 R12: 00007f7fdefff000 R13: 00007f7fdefffcd8 R14: 00007f7fdefffce0 R15: 00007f7fdefffcd8 </TASK> [3]: https://lore.kernel.org/netdev/20230208004245.83497-1-kuniyu@amazon.com/ Fixes: b5fc29233d28 ("inet6: Remove inet6_destroy_sock() in sk->sk_prot->destroy().") Reported-by: syzbot <syzkaller@googlegroups.com> Reported-by: Christoph Paasch <christophpaasch@icloud.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-02-09 16:22:02 -08:00