- 25 8月, 2017 12 次提交
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由 Eric Biggers 提交于
commit bbb03029 ("strparser: Generalize strparser") added more function pointers to 'struct strp_callbacks'; however, kcm_attach() was not updated to initialize them. This could cause the ->lock() and/or ->unlock() function pointers to be set to garbage values, causing a crash in strp_work(). Fix the bug by moving the callback structs into static memory, so unspecified members are zeroed. Also constify them while we're at it. This bug was found by syzkaller, which encountered the following splat: IP: 0x55 PGD 3b1ca067 P4D 3b1ca067 PUD 3b12f067 PMD 0 Oops: 0010 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 2 PID: 1194 Comm: kworker/u8:1 Not tainted 4.13.0-rc4-next-20170811 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: kstrp strp_work task: ffff88006bb0e480 task.stack: ffff88006bb10000 RIP: 0010:0x55 RSP: 0018:ffff88006bb17540 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff88006ce4bd60 RCX: 0000000000000000 RDX: 1ffff1000d9c97bd RSI: 0000000000000000 RDI: ffff88006ce4bc48 RBP: ffff88006bb17558 R08: ffffffff81467ab2 R09: 0000000000000000 R10: ffff88006bb17438 R11: ffff88006bb17940 R12: ffff88006ce4bc48 R13: ffff88003c683018 R14: ffff88006bb17980 R15: ffff88003c683000 FS: 0000000000000000(0000) GS:ffff88006de00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000055 CR3: 000000003c145000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2098 worker_thread+0x223/0x1860 kernel/workqueue.c:2233 kthread+0x35e/0x430 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 Code: Bad RIP value. RIP: 0x55 RSP: ffff88006bb17540 CR2: 0000000000000055 ---[ end trace f0e4920047069cee ]--- Here is a C reproducer (requires CONFIG_BPF_SYSCALL=y and CONFIG_AF_KCM=y): #include <linux/bpf.h> #include <linux/kcm.h> #include <linux/types.h> #include <stdint.h> #include <sys/ioctl.h> #include <sys/socket.h> #include <sys/syscall.h> #include <unistd.h> static const struct bpf_insn bpf_insns[3] = { { .code = 0xb7 }, /* BPF_MOV64_IMM(0, 0) */ { .code = 0x95 }, /* BPF_EXIT_INSN() */ }; static const union bpf_attr bpf_attr = { .prog_type = 1, .insn_cnt = 2, .insns = (uintptr_t)&bpf_insns, .license = (uintptr_t)"", }; int main(void) { int bpf_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &bpf_attr, sizeof(bpf_attr)); int inet_fd = socket(AF_INET, SOCK_STREAM, 0); int kcm_fd = socket(AF_KCM, SOCK_DGRAM, 0); ioctl(kcm_fd, SIOCKCMATTACH, &(struct kcm_attach) { .fd = inet_fd, .bpf_fd = bpf_fd }); } Fixes: bbb03029 ("strparser: Generalize strparser") Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Tom Herbert <tom@quantonium.net> Signed-off-by: NEric Biggers <ebiggers@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jakub Sitnicki 提交于
When forwarding or sending out an ICMPv6 error, look at the embedded packet that triggered the error and compute a flow hash over its headers. This let's us route the ICMP error together with the flow it belongs to when multipath (ECMP) routing is in use, which in turn makes Path MTU Discovery work in ECMP load-balanced or anycast setups (RFC 7690). Granted, end-hosts behind the ECMP router (aka servers) need to reflect the IPv6 Flow Label for PMTUD to work. The code is organized to be in parallel with ipv4 stack: ip_multipath_l3_keys -> ip6_multipath_l3_keys fib_multipath_hash -> rt6_multipath_hash Signed-off-by: NJakub Sitnicki <jkbs@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jakub Sitnicki 提交于
Allow for functions that fill out the IPv6 flow info to also pass a hash computed over the skb contents. The hash value will drive the multipath routing decisions. This is intended for special treatment of ICMPv6 errors, where we would like to make a routing decision based on the flow identifying the offending IPv6 datagram that triggered the error, rather than the flow of the ICMP error itself. Signed-off-by: NJakub Sitnicki <jkbs@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 David S. Miller 提交于
One too many arguments compared to the non-stub version. Reported-by: Nkbuild test robot <fengguang.wu@intel.com> Fixes: ffd3cdcc ("devlink: Add support for dynamic table size") Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jakub Sitnicki 提交于
Reflecting IPv6 Flow Label at server nodes is useful in environments that employ multipath routing to load balance the requests. As "IPv6 Flow Label Reflection" standard draft [1] points out - ICMPv6 PTB error messages generated in response to a downstream packets from the server can be routed by a load balancer back to the original server without looking at transport headers, if the server applies the flow label reflection. This enables the Path MTU Discovery past the ECMP router in load-balance or anycast environments where each server node is reachable by only one path. Introduce a sysctl to enable flow label reflection per net namespace for all newly created sockets. Same could be earlier achieved only per socket by setting the IPV6_FL_F_REFLECT flag for the IPV6_FLOWLABEL_MGR socket option. [1] https://tools.ietf.org/html/draft-wang-6man-flow-label-reflection-01Signed-off-by: NJakub Sitnicki <jkbs@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jesper Dangaard Brouer 提交于
Remove the net_device string name from the xdp_exception tracepoint, like the xdp_redirect tracepoint. Align the TP_STRUCT to have common entries between these two tracepoint. Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com> Acked-by: NDaniel Borkmann <daniel@iogearbox.net> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jesper Dangaard Brouer 提交于
There is too much overhead in the current trace_xdp_redirect tracepoint as it does strcpy and strlen on the net_device names. Besides, exposing the ifindex/index is actually the information that is needed in the tracepoint to diagnose issues. When a lookup fails (either ifindex or devmap index) then there is a need for saying which to_index that have issues. V2: Adjust args to be aligned with trace_xdp_exception. Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com> Acked-by: NDaniel Borkmann <daniel@iogearbox.net> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jesper Dangaard Brouer 提交于
If the xdp_do_generic_redirect() call fails, it trigger the trace_xdp_exception tracepoint. It seems better to use the same tracepoint trace_xdp_redirect, as the native xdp_do_redirect{,_map} does. Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com> Acked-by: NDaniel Borkmann <daniel@iogearbox.net> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Arkadi Sharshevsky 提交于
The entry clear routine can be shared between the drivers, thus it is moved inside devlink. Signed-off-by: NArkadi Sharshevsky <arkadis@mellanox.com> Signed-off-by: NJiri Pirko <jiri@mellanox.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Arkadi Sharshevsky 提交于
Up until now the dpipe table's size was static and known at registration time. The host table does not have constant size and it is resized in dynamic manner. In order to support this behavior the size is changed to be obtained dynamically via an op. This patch also adjust the current dpipe table for the new API. Signed-off-by: NArkadi Sharshevsky <arkadis@mellanox.com> Signed-off-by: NJiri Pirko <jiri@mellanox.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Arkadi Sharshevsky 提交于
This will be used by the IPv4 host table which will be introduced in the following patches. This header is global and can be reused by many drivers. Signed-off-by: NArkadi Sharshevsky <arkadis@mellanox.com> Signed-off-by: NJiri Pirko <jiri@mellanox.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Arkadi Sharshevsky 提交于
This will be used by the IPv4 host table which will be introduced in the following patches. This header is global and can be reused by many drivers. Signed-off-by: NArkadi Sharshevsky <arkadis@mellanox.com> Signed-off-by: NJiri Pirko <jiri@mellanox.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 24 8月, 2017 7 次提交
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由 Matan Barak 提交于
The current code stores fte_match_param in the software representation of FTEs and FGs. fte_match_param contains a large reserved area at the bottom of the struct. Since downstream patches are going to hash this part, we would like to avoid doing so on a reserved part. Signed-off-by: NMatan Barak <matanb@mellanox.com> Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
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由 Gal Pressman 提交于
mlx5_core_wq is no longer being used and should be removed from the code. Signed-off-by: NGal Pressman <galp@mellanox.com> Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
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由 Edward Cree 提交于
The liveness tracking algorithm is quite subtle; add comments to explain it. Signed-off-by: NEdward Cree <ecree@solarflare.com> Acked-by: NAlexei Starovoitov <ast@kernel.org> Acked-by: NDaniel Borkmann <daniel@iogearbox.net> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Edward Cree 提交于
The optimisation it does is broken when the 'new' register value has a variable offset and the 'old' was constant. I broke it with my pointer types unification (see Fixes tag below), before which the 'new' value would have type PTR_TO_MAP_VALUE_ADJ and would thus not compare equal; other changes in that patch mean that its original behaviour (ignore min/max values) cannot be restored. Tests on a sample set of cilium programs show no change in count of processed instructions. Fixes: f1174f77 ("bpf/verifier: rework value tracking") Signed-off-by: NEdward Cree <ecree@solarflare.com> Acked-by: NAlexei Starovoitov <ast@kernel.org> Acked-by: NDaniel Borkmann <daniel@iogearbox.net> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jiri Pirko 提交于
Add helpers to find out if a gact instance is goto_chain termination action and to get chain index. Signed-off-by: NJiri Pirko <jiri@mellanox.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Antoine Ténart 提交于
The TSO header size was defined in many drivers. Factorize the code and define its size in net/tso.h. Signed-off-by: NAntoine Tenart <antoine.tenart@free-electrons.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Mike Maloney 提交于
When SOF_TIMESTAMPING_RX_SOFTWARE is enabled for tcp sockets, return the timestamp corresponding to the highest sequence number data returned. Previously the skb->tstamp is overwritten when a TCP packet is placed in the out of order queue. While the packet is in the ooo queue, save the timestamp in the TCB_SKB_CB. This space is shared with the gso_* options which are only used on the tx path, and a previously unused 4 byte hole. When skbs are coalesced either in the sk_receive_queue or the out_of_order_queue always choose the timestamp of the appended skb to maintain the invariant of returning the timestamp of the last byte in the recvmsg buffer. Signed-off-by: NMike Maloney <maloney@google.com> Acked-by: NWillem de Bruijn <willemb@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 23 8月, 2017 2 次提交
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由 William Tu 提交于
The patch adds ERSPAN type II tunnel support. The implementation is based on the draft at [1]. One of the purposes is for Linux box to be able to receive ERSPAN monitoring traffic sent from the Cisco switch, by creating a ERSPAN tunnel device. In addition, the patch also adds ERSPAN TX, so Linux virtual switch can redirect monitored traffic to the ERSPAN tunnel device. The traffic will be encapsulated into ERSPAN and sent out. The implementation reuses tunnel key as ERSPAN session ID, and field 'erspan' as ERSPAN Index fields: ./ip link add dev ers11 type erspan seq key 100 erspan 123 \ local 172.16.1.200 remote 172.16.1.100 To use the above device as ERSPAN receiver, configure Nexus 5000 switch as below: monitor session 100 type erspan-source erspan-id 123 vrf default destination ip 172.16.1.200 source interface Ethernet1/11 both source interface Ethernet1/12 both no shut monitor erspan origin ip-address 172.16.1.100 global [1] https://tools.ietf.org/html/draft-foschiano-erspan-01 [2] iproute2 patch: http://marc.info/?l=linux-netdev&m=150306086924951&w=2 [3] test script: http://marc.info/?l=linux-netdev&m=150231021807304&w=2Signed-off-by: NWilliam Tu <u9012063@gmail.com> Signed-off-by: NMeenakshi Vohra <mvohra@vmware.com> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Tonghao Zhang 提交于
Signed-off-by: NTonghao Zhang <xiangxia.m.yue@gmail.com> Acked-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 22 8月, 2017 3 次提交
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由 Gao Feng 提交于
Add the invalid handle "0" check to avoid unnecessary search, because the qdisc uses the skb->priority as the handle value to look up, and it is "0" usually. Signed-off-by: NGao Feng <gfree.wind@vip.163.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Oleg Nesterov 提交于
This was reported many times, and this was even mentioned in commit 52ee2dfd ("pids: refactor vnr/nr_ns helpers to make them safe") but somehow nobody bothered to fix the obvious problem: task_tgid_nr_ns() is not safe because task->group_leader points to nowhere after the exiting task passes exit_notify(), rcu_read_lock() can not help. We really need to change __unhash_process() to nullify group_leader, parent, and real_parent, but this needs some cleanups. Until then we can turn task_tgid_nr_ns() into another user of __task_pid_nr_ns() and fix the problem. Reported-by: NTroy Kensinger <tkensinger@google.com> Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Florian Westphal 提交于
compile tested only, but saw no warnings/errors with allmodconfig build. Signed-off-by: NFlorian Westphal <fw@strlen.de> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 21 8月, 2017 1 次提交
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由 Konstantin Khlebnikov 提交于
This important to call qdisc_tree_reduce_backlog() after changing queue length. Parent qdisc should deactivate class in ->qlen_notify() called from qdisc_tree_reduce_backlog() but this happens only if qdisc->q.qlen in zero. Missed class deactivations leads to crashes/warnings at picking packets from empty qdisc and corrupting state at reactivating this class in future. Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru> Fixes: 86a7996c ("net_sched: introduce qdisc_replace() helper") Acked-by: NCong Wang <xiyou.wangcong@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 20 8月, 2017 5 次提交
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由 Eran Ben Elisha 提交于
Add outbound_pci_buffer_overflow to ethtool output for monitoring the number of packets that were dropped due to lack of PCIe buffers on receive path from NIC port toward the host(s). This counter is valid only in case that tx_overflow_buffer_pkt is supported in MCAM enhanced features. Signed-off-by: NEran Ben Elisha <eranbe@mellanox.com> Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
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由 Gal Pressman 提交于
Add capability bit in PCAM register and counters to PPCNT register. Signed-off-by: NGal Pressman <galp@mellanox.com> Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
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由 Gal Pressman 提交于
Add capability bit in MCAM register and counters to MPCNT register. Signed-off-by: NGal Pressman <galp@mellanox.com> Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
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由 David S. Miller 提交于
Reported-by: Nkbuild test robot <fengguang.wu@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Martin KaFai Lau 提交于
The current map creation API does not allow to provide the numa-node preference. The memory usually comes from where the map-creation-process is running. The performance is not ideal if the bpf_prog is known to always run in a numa node different from the map-creation-process. One of the use case is sharding on CPU to different LRU maps (i.e. an array of LRU maps). Here is the test result of map_perf_test on the INNER_LRU_HASH_PREALLOC test if we force the lru map used by CPU0 to be allocated from a remote numa node: [ The machine has 20 cores. CPU0-9 at node 0. CPU10-19 at node 1 ] ># taskset -c 10 ./map_perf_test 512 8 1260000 8000000 5:inner_lru_hash_map_perf pre-alloc 1628380 events per sec 4:inner_lru_hash_map_perf pre-alloc 1626396 events per sec 3:inner_lru_hash_map_perf pre-alloc 1626144 events per sec 6:inner_lru_hash_map_perf pre-alloc 1621657 events per sec 2:inner_lru_hash_map_perf pre-alloc 1621534 events per sec 1:inner_lru_hash_map_perf pre-alloc 1620292 events per sec 7:inner_lru_hash_map_perf pre-alloc 1613305 events per sec 0:inner_lru_hash_map_perf pre-alloc 1239150 events per sec #<<< After specifying numa node: ># taskset -c 10 ./map_perf_test 512 8 1260000 8000000 5:inner_lru_hash_map_perf pre-alloc 1629627 events per sec 3:inner_lru_hash_map_perf pre-alloc 1628057 events per sec 1:inner_lru_hash_map_perf pre-alloc 1623054 events per sec 6:inner_lru_hash_map_perf pre-alloc 1616033 events per sec 2:inner_lru_hash_map_perf pre-alloc 1614630 events per sec 4:inner_lru_hash_map_perf pre-alloc 1612651 events per sec 7:inner_lru_hash_map_perf pre-alloc 1609337 events per sec 0:inner_lru_hash_map_perf pre-alloc 1619340 events per sec #<<< This patch adds one field, numa_node, to the bpf_attr. Since numa node 0 is a valid node, a new flag BPF_F_NUMA_NODE is also added. The numa_node field is honored if and only if the BPF_F_NUMA_NODE flag is set. Numa node selection is not supported for percpu map. This patch does not change all the kmalloc. F.e. 'htab = kzalloc()' is not changed since the object is small enough to stay in the cache. Signed-off-by: NMartin KaFai Lau <kafai@fb.com> Acked-by: NDaniel Borkmann <daniel@iogearbox.net> Acked-by: NAlexei Starovoitov <ast@fb.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 19 8月, 2017 10 次提交
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由 stephen hemminger 提交于
The show and store functions don't need/use the attribute. Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 stephen hemminger 提交于
This can be const. Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 stephen hemminger 提交于
These functions are wrapper arount class_create_file which can take a const attribute. Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Lendacky, Thomas 提交于
There are currently macros to set and test an ETHTOOL_LINK_MODE_ setting, but not to clear one. Add a macro to clear an ETHTOOL_LINK_MODE_ setting. Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Jesper Dangaard Brouer 提交于
The return error code need to be included in the tracepoint xdp:xdp_redirect, else its not possible to distinguish successful or failed XDP_REDIRECT transmits. XDP have no queuing mechanism. Thus, it is fairly easily to overrun a NIC transmit queue. The eBPF program invoking helpers (bpf_redirect or bpf_redirect_map) to redirect a packet doesn't get any feedback whether the packet was actually transmitted. Info on failed transmits in the tracepoint xdp:xdp_redirect, is interesting as this opens for providing a feedback-loop to the receiving XDP program. Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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This is useful for directly looking up a task based on class id rather than having to scan through all open file descriptors. Signed-off-by: NSasha Levin <alexander.levin@verizon.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Michal Hocko 提交于
Wenwei Tao has noticed that our current assumption that the oom victim is dying and never doing any visible changes after it dies, and so the oom_reaper can tear it down, is not entirely true. __task_will_free_mem consider a task dying when SIGNAL_GROUP_EXIT is set but do_group_exit sends SIGKILL to all threads _after_ the flag is set. So there is a race window when some threads won't have fatal_signal_pending while the oom_reaper could start unmapping the address space. Moreover some paths might not check for fatal signals before each PF/g-u-p/copy_from_user. We already have a protection for oom_reaper vs. PF races by checking MMF_UNSTABLE. This has been, however, checked only for kernel threads (use_mm users) which can outlive the oom victim. A simple fix would be to extend the current check in handle_mm_fault for all tasks but that wouldn't be sufficient because the current check assumes that a kernel thread would bail out after EFAULT from get_user*/copy_from_user and never re-read the same address which would succeed because the PF path has established page tables already. This seems to be the case for the only existing use_mm user currently (virtio driver) but it is rather fragile in general. This is even more fragile in general for more complex paths such as generic_perform_write which can re-read the same address more times (e.g. iov_iter_copy_from_user_atomic to fail and then iov_iter_fault_in_readable on retry). Therefore we have to implement MMF_UNSTABLE protection in a robust way and never make a potentially corrupted content visible. That requires to hook deeper into the PF path and check for the flag _every time_ before a pte for anonymous memory is established (that means all !VM_SHARED mappings). The corruption can be triggered artificially (http://lkml.kernel.org/r/201708040646.v746kkhC024636@www262.sakura.ne.jp) but there doesn't seem to be any real life bug report. The race window should be quite tight to trigger most of the time. Link: http://lkml.kernel.org/r/20170807113839.16695-3-mhocko@kernel.org Fixes: aac45363 ("mm, oom: introduce oom reaper") Signed-off-by: NMichal Hocko <mhocko@suse.com> Reported-by: NWenwei Tao <wenwei.tww@alibaba-inc.com> Tested-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andrea Argangeli <andrea@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Pavel Tatashin 提交于
There is existing use after free bug when deferred struct pages are enabled: The memblock_add() allocates memory for the memory array if more than 128 entries are needed. See comment in e820__memblock_setup(): * The bootstrap memblock region count maximum is 128 entries * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries * than that - so allow memblock resizing. This memblock memory is freed here: free_low_memory_core_early() We access the freed memblock.memory later in boot when deferred pages are initialized in this path: deferred_init_memmap() for_each_mem_pfn_range() __next_mem_pfn_range() type = &memblock.memory; One possible explanation for why this use-after-free hasn't been hit before is that the limit of INIT_MEMBLOCK_REGIONS has never been exceeded at least on systems where deferred struct pages were enabled. Tested by reducing INIT_MEMBLOCK_REGIONS down to 4 from the current 128, and verifying in qemu that this code is getting excuted and that the freed pages are sane. Link: http://lkml.kernel.org/r/1502485554-318703-2-git-send-email-pasha.tatashin@oracle.com Fixes: 7e18adb4 ("mm: meminit: initialise remaining struct pages in parallel with kswapd") Signed-off-by: NPavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: NSteven Sistare <steven.sistare@oracle.com> Reviewed-by: NDaniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: NBob Picco <bob.picco@oracle.com> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Luis R. Rodriguez 提交于
These are the few pending fixes I have queued up for v4.13-final. One is a a generic regression fix for recursive loops on kmod and the other one is a trivial print out correction. During the v4.13 development we assumed that recursive kmod loops were no longer possible. Clearly that is not true. The regression fix makes use of a new killable wait. We use a killable wait to be paranoid in how signals might be sent to modprobe and only accept a proper SIGKILL. The signal will only be available to userspace to issue *iff* a thread has already entered a wait state, and that happens only if we've already throttled after 50 kmod threads have been hit. Note that although it may seem excessive to trigger a failure afer 5 seconds if all kmod thread remain busy, prior to the series of changes that went into v4.13 we would actually *always* fatally fail any request which came in if the limit was already reached. The new waiting implemented in v4.13 actually gives us *more* breathing room -- the wait for 5 seconds is a wait for *any* kmod thread to finish. We give up and fail *iff* no kmod thread has finished and they're *all* running straight for 5 consecutive seconds. If 50 kmod threads are running consecutively for 5 seconds something else must be really bad. Recursive loops with kmod are bad but they're also hard to implement properly as a selftest without currently fooling current userspace tools like kmod [1]. For instance kmod will complain when you run depmod if it finds a recursive loop with symbol dependency between modules as such this type of recursive loop cannot go upstream as the modules_install target will fail after running depmod. These tests already exist on userspace kmod upstream though (refer to the testsuite/module-playground/mod-loop-*.c files). The same is not true if request_module() is used though, or worst if aliases are used. Likewise the issue with 64-bit kernels booting 32-bit userspace without a binfmt handler built-in is also currently not detected and proactively avoided by userspace kmod tools, or kconfig for all architectures. Although we could complain in the kernel when some of these individual recursive issues creep up, proactively avoiding these situations in userspace at build time is what we should keep striving for. Lastly, since recursive loops could happen with kmod it may mean recursive loops may also be possible with other kernel usermode helpers, this should be investigated and long term if we can come up with a more sensible generic solution even better! [0] https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git/log/?h=20170809-kmod-for-v4.13-final [1] https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git This patch (of 3): This wait is similar to wait_event_interruptible_timeout() but only accepts SIGKILL interrupt signal. Other signals are ignored. Link: http://lkml.kernel.org/r/20170809234635.13443-2-mcgrof@kernel.orgSigned-off-by: NLuis R. Rodriguez <mcgrof@kernel.org> Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Jessica Yu <jeyu@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Michal Marek <mmarek@suse.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Daniel Mentz <danielmentz@google.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Matt Redfearn <matt.redfearn@imgetc.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
Jaegeuk and Brad report a NULL pointer crash when writeback ending tries to update the memcg stats: BUG: unable to handle kernel NULL pointer dereference at 00000000000003b0 IP: test_clear_page_writeback+0x12e/0x2c0 [...] RIP: 0010:test_clear_page_writeback+0x12e/0x2c0 Call Trace: <IRQ> end_page_writeback+0x47/0x70 f2fs_write_end_io+0x76/0x180 [f2fs] bio_endio+0x9f/0x120 blk_update_request+0xa8/0x2f0 scsi_end_request+0x39/0x1d0 scsi_io_completion+0x211/0x690 scsi_finish_command+0xd9/0x120 scsi_softirq_done+0x127/0x150 __blk_mq_complete_request_remote+0x13/0x20 flush_smp_call_function_queue+0x56/0x110 generic_smp_call_function_single_interrupt+0x13/0x30 smp_call_function_single_interrupt+0x27/0x40 call_function_single_interrupt+0x89/0x90 RIP: 0010:native_safe_halt+0x6/0x10 (gdb) l *(test_clear_page_writeback+0x12e) 0xffffffff811bae3e is in test_clear_page_writeback (./include/linux/memcontrol.h:619). 614 mod_node_page_state(page_pgdat(page), idx, val); 615 if (mem_cgroup_disabled() || !page->mem_cgroup) 616 return; 617 mod_memcg_state(page->mem_cgroup, idx, val); 618 pn = page->mem_cgroup->nodeinfo[page_to_nid(page)]; 619 this_cpu_add(pn->lruvec_stat->count[idx], val); 620 } 621 622 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, 623 gfp_t gfp_mask, The issue is that writeback doesn't hold a page reference and the page might get freed after PG_writeback is cleared (and the mapping is unlocked) in test_clear_page_writeback(). The stat functions looking up the page's node or zone are safe, as those attributes are static across allocation and free cycles. But page->mem_cgroup is not, and it will get cleared if we race with truncation or migration. It appears this race window has been around for a while, but less likely to trigger when the memcg stats were updated first thing after PG_writeback is cleared. Recent changes reshuffled this code to update the global node stats before the memcg ones, though, stretching the race window out to an extent where people can reproduce the problem. Update test_clear_page_writeback() to look up and pin page->mem_cgroup before clearing PG_writeback, then not use that pointer afterward. It is a partial revert of 62cccb8c ("mm: simplify lock_page_memcg()") but leaves the pageref-holding callsites that aren't affected alone. Link: http://lkml.kernel.org/r/20170809183825.GA26387@cmpxchg.org Fixes: 62cccb8c ("mm: simplify lock_page_memcg()") Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Reported-by: NJaegeuk Kim <jaegeuk@kernel.org> Tested-by: NJaegeuk Kim <jaegeuk@kernel.org> Reported-by: NBradley Bolen <bradleybolen@gmail.com> Tested-by: NBrad Bolen <bradleybolen@gmail.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> [4.6+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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