talos-op-linux/net/core, branch master

page_pool: refill page when alloc.count of pool is zero

2020-02-13T22:11:51+00:00

"do {} while" in page_pool_refill_alloc_cache will always refill page once whether refill is true or false, and whether alloc.count of pool is less than PP_ALLOC_CACHE_REFILL or not this is wrong, and will cause overflow of pool->alloc.cache the caller of __page_pool_get_cached should provide guarantee that pool->alloc.cache is safe to access, so in_serving_softirq should be removed as suggested by Jesper Dangaard Brouer in https://patchwork.ozlabs.org/patch/1233713/ so fix this issue by calling page_pool_refill_alloc_cache() only when pool->alloc.count is zero Fixes: 44768decb7c0 ("page_pool: handle page recycle for NUMA_NO_NODE condition") Signed-off-by: Li RongQing Suggested-by: Jesper Dangaard Brouer Acked-by: Jesper Dangaard Brouer Acked-by: Ilias Apalodimas Signed-off-by: David S. Miller

core: Don't skip generic XDP program execution for cloned SKBs

2020-02-12T01:01:29+00:00

The current generic XDP handler skips execution of XDP programs entirely if an SKB is marked as cloned. This leads to some surprising behaviour, as packets can end up being cloned in various ways, which will make an XDP program not see all the traffic on an interface. This was discovered by a simple test case where an XDP program that always returns XDP_DROP is installed on a veth device. When combining this with the Scapy packet sniffer (which uses an AF_PACKET) socket on the sending side, SKBs reliably end up in the cloned state, causing them to be passed through to the receiving interface instead of being dropped. A minimal reproducer script for this is included below. This patch fixed the issue by simply triggering the existing linearisation code for cloned SKBs instead of skipping the XDP program execution. This behaviour is in line with the behaviour of the native XDP implementation for the veth driver, which will reallocate and copy the SKB data if the SKB is marked as shared. Reproducer Python script (requires BCC and Scapy): from scapy.all import TCP, IP, Ether, sendp, sniff, AsyncSniffer, Raw, UDP from bcc import BPF import time, sys, subprocess, shlex SKB_MODE = (1 << 1) DRV_MODE = (1 << 2) PYTHON=sys.executable def client(): time.sleep(2) # Sniffing on the sender causes skb_cloned() to be set s = AsyncSniffer() s.start() for p in range(10): sendp(Ether(dst="aa:aa:aa:aa:aa:aa", src="cc:cc:cc:cc:cc:cc")/IP()/UDP()/Raw("Test"), verbose=False) time.sleep(0.1) s.stop() return 0 def server(mode): prog = BPF(text="int dummy_drop(struct xdp_md *ctx) {return XDP_DROP;}") func = prog.load_func("dummy_drop", BPF.XDP) prog.attach_xdp("a_to_b", func, mode) time.sleep(1) s = sniff(iface="a_to_b", count=10, timeout=15) if len(s): print(f"Got {len(s)} packets - should have gotten 0") return 1 else: print("Got no packets - as expected") return 0 if len(sys.argv) < 2: print(f"Usage: {sys.argv[0]} ") sys.exit(1) if sys.argv[1] == "client": sys.exit(client()) elif sys.argv[1] == "server": mode = SKB_MODE if sys.argv[2] == 'skb' else DRV_MODE sys.exit(server(mode)) else: try: mode = sys.argv[1] if mode not in ('skb', 'drv'): print(f"Usage: {sys.argv[0]} ") sys.exit(1) print(f"Running in {mode} mode") for cmd in [ 'ip netns add netns_a', 'ip netns add netns_b', 'ip -n netns_a link add a_to_b type veth peer name b_to_a netns netns_b', # Disable ipv6 to make sure there's no address autoconf traffic 'ip netns exec netns_a sysctl -qw net.ipv6.conf.a_to_b.disable_ipv6=1', 'ip netns exec netns_b sysctl -qw net.ipv6.conf.b_to_a.disable_ipv6=1', 'ip -n netns_a link set dev a_to_b address aa:aa:aa:aa:aa:aa', 'ip -n netns_b link set dev b_to_a address cc:cc:cc:cc:cc:cc', 'ip -n netns_a link set dev a_to_b up', 'ip -n netns_b link set dev b_to_a up']: subprocess.check_call(shlex.split(cmd)) server = subprocess.Popen(shlex.split(f"ip netns exec netns_a {PYTHON} {sys.argv[0]} server {mode}")) client = subprocess.Popen(shlex.split(f"ip netns exec netns_b {PYTHON} {sys.argv[0]} client")) client.wait() server.wait() sys.exit(server.returncode) finally: subprocess.run(shlex.split("ip netns delete netns_a")) subprocess.run(shlex.split("ip netns delete netns_b")) Fixes: d445516966dc ("net: xdp: support xdp generic on virtual devices") Reported-by: Stepan Horacek Suggested-by: Paolo Abeni Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2020-02-08T14:01:03+00:00

Daniel Borkmann says: ==================== pull-request: bpf 2020-02-07 The following pull-request contains BPF updates for your *net* tree. We've added 15 non-merge commits during the last 10 day(s) which contain a total of 12 files changed, 114 insertions(+), 31 deletions(-). The main changes are: 1) Various BPF sockmap fixes related to RCU handling in the map's tear- down code, from Jakub Sitnicki. 2) Fix macro state explosion in BPF sk_storage map when calculating its bucket_log on allocation, from Martin KaFai Lau. 3) Fix potential BPF sockmap update race by rechecking socket's established state under lock, from Lorenz Bauer. 4) Fix crash in bpftool on missing xlated instructions when kptr_restrict sysctl is set, from Toke Høiland-Jørgensen. 5) Fix i40e's XSK wakeup code to return proper error in busy state and various misc fixes in xdpsock BPF sample code, from Maciej Fijalkowski. 6) Fix the way modifiers are skipped in BTF in the verifier while walking pointers to avoid program rejection, from Alexei Starovoitov. 7) Fix Makefile for runqslower BPF tool to i) rebuild on libbpf changes and ii) to fix undefined reference linker errors for older gcc version due to order of passed gcc parameters, from Yulia Kartseva and Song Liu. 8) Fix a trampoline_count BPF kselftest warning about missing braces around initializer, from Andrii Nakryiko. 9) Fix up redundant "HAVE" prefix from large INSN limit kernel probe in bpftool, from Michal Rostecki. ==================== Signed-off-by: David S. Miller

bpf: Improve bucket_log calculation logic

2020-02-07T22:01:41+00:00

It was reported that the max_t, ilog2, and roundup_pow_of_two macros have exponential effects on the number of states in the sparse checker. This patch breaks them up by calculating the "nbuckets" first so that the "bucket_log" only needs to take ilog2(). In addition, Linus mentioned: Patch looks good, but I'd like to point out that it's not just sparse. You can see it with a simple make net/core/bpf_sk_storage.i grep 'smap->bucket_log = ' net/core/bpf_sk_storage.i | wc and see the end result: 1 365071 2686974 That's one line (the assignment line) that is 2,686,974 characters in length. Now, sparse does happen to react particularly badly to that (I didn't look to why, but I suspect it's just that evaluating all the types that don't actually ever end up getting used ends up being much more expensive than it should be), but I bet it's not good for gcc either. Fixes: 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage") Reported-by: Randy Dunlap Reported-by: Luc Van Oostenryck Suggested-by: Linus Torvalds Signed-off-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann Reviewed-by: Luc Van Oostenryck Link: https://lore.kernel.org/bpf/20200207081810.3918919-1-kafai@fb.com

bpf, sockhash: Synchronize_rcu before free'ing map

2020-02-07T21:36:26+00:00

We need to have a synchronize_rcu before free'ing the sockhash because any outstanding psock references will have a pointer to the map and when they use it, this could trigger a use after free. This is a sister fix for sockhash, following commit 2bb90e5cc90e ("bpf: sockmap, synchronize_rcu before free'ing map") which addressed sockmap, which comes from a manual audit. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200206111652.694507-3-jakub@cloudflare.com

bpf, sockmap: Don't sleep while holding RCU lock on tear-down

2020-02-07T21:36:26+00:00

rcu_read_lock is needed to protect access to psock inside sock_map_unref when tearing down the map. However, we can't afford to sleep in lock_sock while in RCU read-side critical section. Grab the RCU lock only after we have locked the socket. This fixes RCU warnings triggerable on a VM with 1 vCPU when free'ing a sockmap/sockhash that contains at least one socket: | ============================= | WARNING: suspicious RCU usage | 5.5.0-04005-g8fc91b972b73 #450 Not tainted | ----------------------------- | include/linux/rcupdate.h:272 Illegal context switch in RCU read-side critical section! | | other info that might help us debug this: | | | rcu_scheduler_active = 2, debug_locks = 1 | 4 locks held by kworker/0:1/62: | #0: ffff88813b019748 ((wq_completion)events){+.+.}, at: process_one_work+0x1d7/0x5e0 | #1: ffffc900000abe50 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x1d7/0x5e0 | #2: ffffffff82065d20 (rcu_read_lock){....}, at: sock_map_free+0x5/0x170 | #3: ffff8881368c5df8 (&stab->lock){+...}, at: sock_map_free+0x64/0x170 | | stack backtrace: | CPU: 0 PID: 62 Comm: kworker/0:1 Not tainted 5.5.0-04005-g8fc91b972b73 #450 | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 | Workqueue: events bpf_map_free_deferred | Call Trace: | dump_stack+0x71/0xa0 | ___might_sleep+0x105/0x190 | lock_sock_nested+0x28/0x90 | sock_map_free+0x95/0x170 | bpf_map_free_deferred+0x58/0x80 | process_one_work+0x260/0x5e0 | worker_thread+0x4d/0x3e0 | kthread+0x108/0x140 | ? process_one_work+0x5e0/0x5e0 | ? kthread_park+0x90/0x90 | ret_from_fork+0x3a/0x50 | ============================= | WARNING: suspicious RCU usage | 5.5.0-04005-g8fc91b972b73-dirty #452 Not tainted | ----------------------------- | include/linux/rcupdate.h:272 Illegal context switch in RCU read-side critical section! | | other info that might help us debug this: | | | rcu_scheduler_active = 2, debug_locks = 1 | 4 locks held by kworker/0:1/62: | #0: ffff88813b019748 ((wq_completion)events){+.+.}, at: process_one_work+0x1d7/0x5e0 | #1: ffffc900000abe50 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x1d7/0x5e0 | #2: ffffffff82065d20 (rcu_read_lock){....}, at: sock_hash_free+0x5/0x1d0 | #3: ffff888139966e00 (&htab->buckets[i].lock){+...}, at: sock_hash_free+0x92/0x1d0 | | stack backtrace: | CPU: 0 PID: 62 Comm: kworker/0:1 Not tainted 5.5.0-04005-g8fc91b972b73-dirty #452 | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 | Workqueue: events bpf_map_free_deferred | Call Trace: | dump_stack+0x71/0xa0 | ___might_sleep+0x105/0x190 | lock_sock_nested+0x28/0x90 | sock_hash_free+0xec/0x1d0 | bpf_map_free_deferred+0x58/0x80 | process_one_work+0x260/0x5e0 | worker_thread+0x4d/0x3e0 | kthread+0x108/0x140 | ? process_one_work+0x5e0/0x5e0 | ? kthread_park+0x90/0x90 | ret_from_fork+0x3a/0x50 Fixes: 7e81a3530206 ("bpf: Sockmap, ensure sock lock held during tear down") Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200206111652.694507-2-jakub@cloudflare.com

bpf, sockmap: Check update requirements after locking

2020-02-07T21:28:04+00:00

It's currently possible to insert sockets in unexpected states into a sockmap, due to a TOCTTOU when updating the map from a syscall. sock_map_update_elem checks that sk->sk_state == TCP_ESTABLISHED, locks the socket and then calls sock_map_update_common. At this point, the socket may have transitioned into another state, and the earlier assumptions don't hold anymore. Crucially, it's conceivable (though very unlikely) that a socket has become unhashed. This breaks the sockmap's assumption that it will get a callback via sk->sk_prot->unhash. Fix this by checking the (fixed) sk_type and sk_protocol without the lock, followed by a locked check of sk_state. Unfortunately it's not possible to push the check down into sock_(map|hash)_update_common, since BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB run before the socket has transitioned from TCP_SYN_RECV into TCP_ESTABLISHED. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Lorenz Bauer Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Sitnicki Link: https://lore.kernel.org/bpf/20200207103713.28175-1-lmb@cloudflare.com

drop_monitor: Do not cancel uninitialized work item

2020-02-07T17:48:36+00:00

Drop monitor uses a work item that takes care of constructing and sending netlink notifications to user space. In case drop monitor never started to monitor, then the work item is uninitialized and not associated with a function. Therefore, a stop command from user space results in canceling an uninitialized work item which leads to the following warning [1]. Fix this by not processing a stop command if drop monitor is not currently monitoring. [1] [ 31.735402] ------------[ cut here ]------------ [ 31.736470] WARNING: CPU: 0 PID: 143 at kernel/workqueue.c:3032 __flush_work+0x89f/0x9f0 ... [ 31.738120] CPU: 0 PID: 143 Comm: dwdump Not tainted 5.5.0-custom-09491-g16d4077796b8 #727 [ 31.741968] RIP: 0010:__flush_work+0x89f/0x9f0 ... [ 31.760526] Call Trace: [ 31.771689] __cancel_work_timer+0x2a6/0x3b0 [ 31.776809] net_dm_cmd_trace+0x300/0xef0 [ 31.777549] genl_rcv_msg+0x5c6/0xd50 [ 31.781005] netlink_rcv_skb+0x13b/0x3a0 [ 31.784114] genl_rcv+0x29/0x40 [ 31.784720] netlink_unicast+0x49f/0x6a0 [ 31.787148] netlink_sendmsg+0x7cf/0xc80 [ 31.790426] ____sys_sendmsg+0x620/0x770 [ 31.793458] ___sys_sendmsg+0xfd/0x170 [ 31.802216] __sys_sendmsg+0xdf/0x1a0 [ 31.806195] do_syscall_64+0xa0/0x540 [ 31.806885] entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 8e94c3bc922e ("drop_monitor: Allow user to start monitoring hardware drops") Signed-off-by: Ido Schimmel Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller

devlink: report 0 after hitting end in region read

2020-02-05T13:23:20+00:00

commit fdd41ec21e15 ("devlink: Return right error code in case of errors for region read") modified the region read code to report errors properly in unexpected cases. In the case where the start_offset and ret_offset match, it unilaterally converted this into an error. This causes an issue for the "dump" version of the command. In this case, the devlink region dump will always report an invalid argument: 000000000000ffd0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 000000000000ffe0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff devlink answers: Invalid argument 000000000000fff0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff This occurs because the expected flow for the dump is to return 0 after there is no further data. The simplest fix would be to stop converting the error code to -EINVAL if start_offset == ret_offset. However, avoid unnecessary work by checking for when start_offset is larger than the region size and returning 0 upfront. Fixes: fdd41ec21e15 ("devlink: Return right error code in case of errors for region read") Signed-off-by: Jacob Keller Acked-by: Jiri Pirko Signed-off-by: David S. Miller

treewide: remove redundant IS_ERR() before error code check

2020-02-04T03:05:27+00:00

'PTR_ERR(p) == -E*' is a stronger condition than IS_ERR(p). Hence, IS_ERR(p) is unneeded. The semantic patch that generates this commit is as follows: // @@ expression ptr; constant error_code; @@ -IS_ERR(ptr) && (PTR_ERR(ptr) == - error_code) +PTR_ERR(ptr) == - error_code // Link: http://lkml.kernel.org/r/20200106045833.1725-1-masahiroy@kernel.org Signed-off-by: Masahiro Yamada Cc: Julia Lawall Acked-by: Stephen Boyd [drivers/clk/clk.c] Acked-by: Bartosz Golaszewski [GPIO] Acked-by: Wolfram Sang [drivers/i2c] Acked-by: Rafael J. Wysocki [acpi/scan.c] Acked-by: Rob Herring Cc: Eric Biggers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds