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【Meeting Notice】openEuler kernel 技术分享第九期 & 双周例会 Time: 2021-08-06 14:00-18:00
by Meeting Book 03 Aug '21

03 Aug '21

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[PATCH openEuler-1.0-LTS 0/2] prefetch bugfix
by Cheng Jian 02 Aug '21

02 Aug '21

prefetch bugfix Li Ruilin (2): bcache: do not collect data insert info created by write_moving bcache: always record start time of a sample drivers/md/bcache/request.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) -- 2.25.1

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[PATCH kernel-4.19 01/10] tcp_comp: add Kconfig for tcp payload compression
by Yang Yingliang 02 Aug '21

02 Aug '21

From: Wei Yongjun <weiyongjun1(a)huawei.com> hulk inclusion category: feature bugzilla: NA CVE: NA ------------------------------------------------- Add config item CONFIG_TCP_COMP for tcp payload compression. This allows payload compression handling of the TCP protocol to be done in-kernel. This patch only adds the CONFIG_TCP_COMP config, tcp compression capability is implemented later. Signed-off-by: Wei Yongjun <weiyongjun1(a)huawei.com> Signed-off-by: Wang Yufen <wangyufen(a)huawei.com> Reviewed-by: Yue Haibing <yuehaibing(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- net/ipv4/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 2e12f848203a4..883a638648e1f 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -754,3 +754,11 @@ config TCP_MD5SIG on the Internet. If unsure, say N. + +config TCP_COMP + bool "TCP: Transport Layer Compression support" + ---help--- + Enable kernel payload compression support for TCP protocol. This allows + payload compression handling of the TCP protocol to be done in-kernel. + + If unsure, say Y. -- 2.25.1

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[PATCH openEuler-1.0-LTS 000/109] backport patches from linux-4.19
by Yang Yingliang 02 Aug '21

02 Aug '21

Al Viro (1): iov_iter_fault_in_readable() should do nothing in xarray case Alex Shi (1): mm: add VM_WARN_ON_ONCE_PAGE() macro Alex Williamson (1): vfio/pci: Handle concurrent vma faults Alexander Ovechkin (1): net: send SYNACK packet with accepted fwmark Anirudh Rayabharam (1): ext4: fix kernel infoleak via ext4_extent_header Casey Chen (1): nvme-pci: do not call nvme_dev_remove_admin from nvme_remove Dan Carpenter (1): scsi: scsi_dh_alua: Fix signedness bug in alua_rtpg() Dimitri John Ledkov (1): lib/decompress_unlz4.c: correctly handle zero-padding around initrds. Dmitry Bogdanov (1): scsi: target: Fix protect handling in WRITE SAME(32) Dmitry Torokhov (1): i2c: core: Disable client irq on reboot/shutdown Eric Dumazet (8): pkt_sched: sch_qfq: fix qfq_change_class() error path vxlan: add missing rcu_read_lock() in neigh_reduce() ipv6: exthdrs: do not blindly use init_net ipv6: fix out-of-bound access in ip6_parse_tlv() tcp: annotate data races around tp->mtu_info ipv6: tcp: drop silly ICMPv6 packet too big messages udp: annotate data races around unix_sk(sk)->gso_size net/tcp_fastopen: fix data races around tfo_active_disable_stamp Gabriel Krisman Bertazi (1): dm multipath: use updated MPATHF_QUEUE_IO on mapping for bio-based mpath Gao Xiang (1): nfs: fix acl memory leak of posix_acl_create() Hangbin Liu (1): net: ip_tunnel: fix mtu calculation for ETHER tunnel devices Hannes Reinecke (1): scsi: scsi_dh_alua: Check for negative result value Haoran Luo (1): tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop. Hugh Dickins (16): mm/thp: fix __split_huge_pmd_locked() on shmem migration entry mm/thp: make is_huge_zero_pmd() safe and quicker mm/thp: try_to_unmap() use TTU_SYNC for safe splitting mm/thp: fix vma_address() if virtual address below file offset mm/thp: unmap_mapping_page() to fix THP truncate_cleanup_page() mm: page_vma_mapped_walk(): use page for pvmw->page mm: page_vma_mapped_walk(): settle PageHuge on entry mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block mm: page_vma_mapped_walk(): crossing page table boundary mm: page_vma_mapped_walk(): add a level of indentation mm: page_vma_mapped_walk(): use goto instead of while (1) mm: page_vma_mapped_walk(): get vma_address_end() earlier mm/thp: fix page_vma_mapped_walk() if THP mapped by ptes mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk() mm, futex: fix shared futex pgoff on shmem huge page Jakub Kicinski (1): net: ip: avoid OOM kills with large UDP sends over loopback Jason Ekstrand (1): dma-buf/sync_file: Don't leak fences on merge failure Jason Gunthorpe (1): vfio-pci: Use io_remap_pfn_range() for PCI IO memory Javed Hasan (1): scsi: libfc: Fix array index out of bound exception Joe Thornber (1): dm space maps: don't reset space map allocation cursor when committing Jue Wang (1): mm/thp: fix page_address_in_vma() on file THP tails Krzysztof Wilczyński (2): ACPI: sysfs: Fix a buffer overrun problem with description_show() PCI/sysfs: Fix dsm_label_utf16s_to_utf8s() buffer overrun Liu Shixin (1): netlabel: Fix memory leak in netlbl_mgmt_add_common Longpeng(Mike) (1): vsock: notify server to shutdown when client has pending signal Maciej Żenczykowski (1): bpf: Do not change gso_size during bpf_skb_change_proto() ManYi Li (1): scsi: sr: Return appropriate error code when disk is ejected Marcelo Henrique Cerri (1): proc: Avoid mixing integer types in mem_rw() Mario Limonciello (1): ACPI: processor idle: Fix up C-state latency if not ordered Miao Wang (1): net/ipv4: swap flow ports when validating source Miaohe Lin (3): mm/rmap: remove unneeded semicolon in page_not_mapped() mm/rmap: use page_not_mapped in try_to_unmap() mm/huge_memory.c: don't discard hugepage if other processes are mapping it Michael S. Tsirkin (1): virtio_net: move tx vq operation under tx queue lock Mike Christie (4): scsi: iscsi: Add iscsi_cls_conn refcount helpers scsi: iscsi: Fix shost->max_id use scsi: qedi: Fix null ref during abort handling scsi: iscsi: Fix iface sysfs attr detection Miklos Szeredi (1): fuse: check connected before queueing on fpq->io Mikulas Patocka (3): dm writecache: fix data corruption when reloading the target dm writecache: return the exact table values that were set dm writecache: fix writing beyond end of underlying device when shrinking Mimi Zohar (1): evm: fix writing <securityfs>/evm overflow Muchun Song (1): writeback: fix obtain a reference to a freeing memcg css Nicolas Dichtel (1): ipv6: fix 'disable_policy' for fwd packets Nikolay Aleksandrov (1): net: bridge: multicast: fix PIM hello router port marking race Odin Ugedal (1): sched/fair: Fix CFS bandwidth hrtimer expiry type Pablo Neira Ayuso (3): netfilter: nft_exthdr: check for IPv6 packet before further processing netfilter: nft_osf: check for TCP packet before further processing netfilter: nft_tproxy: restrict support to TCP and UDP transport protocols Pan Dong (1): ext4: fix avefreec in find_group_orlov Peilin Ye (1): net/sched: act_skbmod: Skip non-Ethernet packets Petr Mladek (2): kthread_worker: split code for canceling the delayed work timer kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync() Petr Pavlu (1): ipmi/watchdog: Stop watchdog timer when the current action is 'none' Quat Le (1): scsi: core: Retry I/O for Notify (Enable Spinup) Required error Richard Fitzgerald (1): lib: vsprintf: Fix handling of number field widths in vsscanf Roberto Sassu (2): evm: Execute evm_inode_init_security() only when an HMAC key is loaded evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded Steffen Klassert (1): xfrm: Fix error reporting in xfrm_state_construct. Stephen Brennan (1): ext4: use ext4_grp_locked_error in mb_find_extent Steven Rostedt (VMware) (1): tracing: Do not reference char * as a string in histograms Sunwook Eom (1): dm verity fec: fix hash block number in verity_fec_decode Taehee Yoo (1): net: validate lwtstate->data before returning from skb_tunnel_info() Thomas Gleixner (1): x86/fpu: Limit xstate copy size in xstateregs_set() Trond Myklebust (3): NFS: nfs_find_open_context() may only select open files NFSv4: Initialise connection to the server in nfs4_alloc_client() NFSv4/pNFS: Don't call _nfs4_pnfs_v3_ds_connect multiple times Tyrel Datwyler (1): scsi: core: Fix bad pointer dereference when ehandler kthread is invalid Vasily Averin (1): netfilter: ctnetlink: suspicious RCU usage in ctnetlink_dump_helpinfo Willy Tarreau (1): ipv6: use prandom_u32() for ID generation Wolfgang Bumiller (1): net: bridge: sync fdb to new unicast-filtering ports Xianting Tian (1): virtio_net: Remove BUG() to avoid machine dead Xie Yongji (3): virtio-blk: Fix memory leak among suspend/resume procedure virtio_net: Fix error handling in virtnet_restore() virtio_console: Assure used length from device is limited Xin Long (1): sctp: update active_key for asoc when old key is being replaced Yajun Deng (1): net: sched: cls_api: Fix the the wrong parameter Yang Shi (1): mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split Yang Yingliang (1): ext4: return error code when ext4_fill_flex_info() fails Yun Zhou (2): seq_buf: Make trace_seq_putmem_hex() support data longer than 8 seq_buf: Fix overflow in seq_buf_putmem_hex() Zhang Yi (2): ext4: correct the cache_nr in tracepoint ext4_es_shrink_exit ext4: remove check for zero nr_to_scan in ext4_es_scan() Zhihao Cheng (1): nvme-pci: don't WARN_ON in nvme_reset_work if ctrl.state is not RESETTING Documentation/ABI/testing/evm | 26 ++- arch/x86/kernel/fpu/regset.c | 2 +- drivers/acpi/device_sysfs.c | 2 +- drivers/acpi/processor_idle.c | 40 +++++ drivers/block/virtio_blk.c | 2 + drivers/char/ipmi/ipmi_watchdog.c | 22 +-- drivers/char/virtio_console.c | 4 +- drivers/dma-buf/sync_file.c | 13 +- drivers/i2c/i2c-core-base.c | 3 + drivers/md/dm-mpath.c | 6 +- drivers/md/dm-verity-fec.c | 2 +- drivers/md/dm-writecache.c | 102 +++++++---- .../md/persistent-data/dm-space-map-disk.c | 9 +- .../persistent-data/dm-space-map-metadata.c | 9 +- drivers/net/virtio_net.c | 29 +++- drivers/net/vxlan.c | 2 + drivers/nvme/host/pci.c | 5 +- drivers/pci/pci-label.c | 2 +- drivers/scsi/be2iscsi/be_main.c | 4 +- drivers/scsi/bnx2i/bnx2i_iscsi.c | 2 +- drivers/scsi/cxgbi/libcxgbi.c | 4 +- drivers/scsi/device_handler/scsi_dh_alua.c | 11 +- drivers/scsi/hosts.c | 1 + drivers/scsi/libfc/fc_rport.c | 13 +- drivers/scsi/libiscsi.c | 7 +- drivers/scsi/qedi/qedi_fw.c | 2 +- drivers/scsi/qedi/qedi_main.c | 2 +- drivers/scsi/scsi_lib.c | 1 + drivers/scsi/scsi_transport_iscsi.c | 102 +++++------ drivers/scsi/sr.c | 2 + drivers/target/target_core_sbc.c | 35 ++-- drivers/vfio/pci/vfio_pci.c | 31 +++- fs/ext4/extents.c | 3 + fs/ext4/extents_status.c | 4 +- fs/ext4/ialloc.c | 11 +- fs/ext4/mballoc.c | 9 +- fs/ext4/super.c | 1 + fs/fs-writeback.c | 9 +- fs/fuse/dev.c | 9 + fs/nfs/inode.c | 4 + fs/nfs/nfs3proc.c | 4 +- fs/nfs/nfs4client.c | 82 ++++----- fs/nfs/pnfs_nfs.c | 52 +++--- fs/proc/base.c | 2 +- include/linux/huge_mm.h | 8 +- include/linux/hugetlb.h | 16 -- include/linux/mm.h | 3 + include/linux/mmdebug.h | 13 ++ include/linux/nfs_fs.h | 1 + include/linux/pagemap.h | 13 +- include/linux/rmap.h | 3 +- include/net/dst_metadata.h | 4 +- include/scsi/scsi_transport_iscsi.h | 2 + kernel/futex.c | 2 +- kernel/kthread.c | 77 ++++++--- kernel/sched/fair.c | 4 +- kernel/trace/ring_buffer.c | 28 ++- kernel/trace/trace_events_hist.c | 6 +- lib/decompress_unlz4.c | 8 + lib/iov_iter.c | 2 +- lib/kstrtox.c | 13 +- lib/kstrtox.h | 2 + lib/seq_buf.c | 8 +- lib/vsprintf.c | 82 +++++---- mm/huge_memory.c | 58 ++++--- mm/hugetlb.c | 5 +- mm/internal.h | 53 ++++-- mm/memory.c | 41 +++++ mm/page_vma_mapped.c | 160 +++++++++++------- mm/pgtable-generic.c | 4 +- mm/rmap.c | 48 +++--- mm/truncate.c | 43 +++-- net/bridge/br_if.c | 17 +- net/bridge/br_multicast.c | 2 + net/core/filter.c | 4 - net/ipv4/fib_frontend.c | 2 + net/ipv4/ip_output.c | 32 ++-- net/ipv4/ip_tunnel.c | 22 ++- net/ipv4/tcp_fastopen.c | 19 ++- net/ipv4/tcp_ipv4.c | 4 +- net/ipv4/tcp_output.c | 1 + net/ipv4/udp.c | 6 +- net/ipv6/exthdrs.c | 31 ++-- net/ipv6/ip6_output.c | 36 ++-- net/ipv6/output_core.c | 28 +-- net/ipv6/tcp_ipv6.c | 22 ++- net/ipv6/udp.c | 2 +- net/netfilter/nf_conntrack_netlink.c | 3 + net/netfilter/nft_exthdr.c | 3 + net/netfilter/nft_osf.c | 5 + net/netfilter/nft_tproxy.c | 9 +- net/netlabel/netlabel_mgmt.c | 19 ++- net/sched/act_skbmod.c | 12 +- net/sched/cls_api.c | 2 +- net/sched/sch_qfq.c | 8 +- net/sctp/auth.c | 2 + net/vmw_vsock/af_vsock.c | 2 +- net/xfrm/xfrm_user.c | 28 +-- security/integrity/evm/evm_main.c | 2 +- security/integrity/evm/evm_secfs.c | 13 +- 100 files changed, 1092 insertions(+), 638 deletions(-) -- 2.25.1

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[PATCH v2 openEuler-1.0-LTS 00/10] tcp compression
by Wang Yufen 02 Aug '21

02 Aug '21

Wang Hai (1): tcp_comp: allow ignore local tcp connections Wang Yufen (6): tcp_comp: add tcp comp option to SYN and SYN-ACK tcp_comp: add init and cleanup hook for compression tcp_comp: only enable compression for give server ports tcp_comp: add stub proto ops for tcp compression socket tcp_comp: implement recvmsg for tcp compression tcp_comp: open configs for tcp compression Wei Yongjun (3): tcp_comp: add Kconfig for tcp payload compression tcp_comp: add sysctl for enable/disable compression tcp_comp: implement sendmsg for tcp compression arch/arm64/configs/hulk_defconfig | 5 +- arch/arm64/configs/openeuler_defconfig | 5 +- arch/x86/configs/hulk_defconfig | 3 + arch/x86/configs/openeuler_defconfig | 5 +- include/linux/tcp.h | 2 +- include/net/inet_sock.h | 3 +- include/net/sock.h | 1 + include/net/tcp.h | 40 ++ net/ipv4/Kconfig | 11 + net/ipv4/Makefile | 1 + net/ipv4/syncookies.c | 2 + net/ipv4/sysctl_net_ipv4.c | 42 ++ net/ipv4/tcp.c | 6 + net/ipv4/tcp_comp.c | 941 +++++++++++++++++++++++++++++++++ net/ipv4/tcp_input.c | 44 +- net/ipv4/tcp_ipv4.c | 2 + net/ipv4/tcp_minisocks.c | 3 + net/ipv4/tcp_output.c | 53 ++ net/ipv6/syncookies.c | 2 + 19 files changed, 1159 insertions(+), 12 deletions(-) create mode 100644 net/ipv4/tcp_comp.c -- 1.8.3

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[PATCH v2 kernel-4.19 00/10] tcp compression
by Wang Yufen 02 Aug '21

02 Aug '21

Wang Hai (1): tcp_comp: allow ignore local tcp connections Wang Yufen (6): tcp_comp: add tcp comp option to SYN and SYN-ACK tcp_comp: add init and cleanup hook for compression tcp_comp: only enable compression for give server ports tcp_comp: add stub proto ops for tcp compression socket tcp_comp: implement recvmsg for tcp compression tcp_comp: open configs for tcp compression Wei Yongjun (3): tcp_comp: add Kconfig for tcp payload compression tcp_comp: add sysctl for enable/disable compression tcp_comp: implement sendmsg for tcp compression arch/arm64/configs/hulk_defconfig | 5 +- arch/arm64/configs/openeuler_defconfig | 5 +- arch/x86/configs/hulk_defconfig | 3 + arch/x86/configs/openeuler_defconfig | 5 +- include/linux/tcp.h | 2 +- include/net/inet_sock.h | 3 +- include/net/sock.h | 1 + include/net/tcp.h | 40 ++ net/ipv4/Kconfig | 11 + net/ipv4/Makefile | 1 + net/ipv4/syncookies.c | 2 + net/ipv4/sysctl_net_ipv4.c | 42 ++ net/ipv4/tcp.c | 6 + net/ipv4/tcp_comp.c | 941 +++++++++++++++++++++++++++++++++ net/ipv4/tcp_input.c | 44 +- net/ipv4/tcp_ipv4.c | 2 + net/ipv4/tcp_minisocks.c | 3 + net/ipv4/tcp_output.c | 53 ++ net/ipv6/syncookies.c | 2 + 19 files changed, 1159 insertions(+), 12 deletions(-) create mode 100644 net/ipv4/tcp_comp.c -- 1.8.3

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[PATCH openEuler-1.0-LTS 00/10] tcp compression
by Wang Yufen 01 Aug '21

01 Aug '21

Wang Hai (1): tcp_comp: allow ignore local tcp connections Wang Yufen (6): tcp_comp: add tcp comp option to SYN and SYN-ACK tcp_comp: add init and cleanup hook for compression tcp_comp: only enable compression for give server ports tcp_comp: add stub proto ops for tcp compression socket tcp_comp: implement recvmsg for tcp compression tcp_comp: open configs for tcp compression Wei Yongjun (3): tcp_comp: add Kconfig for tcp payload compression tcp_comp: add sysctl for enable/disable compression tcp_comp: implement sendmsg for tcp compression arch/arm64/configs/hulk_defconfig | 5 +- arch/arm64/configs/openeuler_defconfig | 5 +- arch/x86/configs/hulk_defconfig | 3 + arch/x86/configs/openeuler_defconfig | 5 +- include/linux/tcp.h | 2 +- include/net/inet_sock.h | 3 +- include/net/sock.h | 1 + include/net/tcp.h | 40 ++ net/ipv4/Kconfig | 11 + net/ipv4/Makefile | 1 + net/ipv4/syncookies.c | 2 + net/ipv4/sysctl_net_ipv4.c | 42 ++ net/ipv4/tcp.c | 6 + net/ipv4/tcp_comp.c | 941 +++++++++++++++++++++++++++++++++ net/ipv4/tcp_input.c | 44 +- net/ipv4/tcp_ipv4.c | 2 + net/ipv4/tcp_minisocks.c | 3 + net/ipv4/tcp_output.c | 53 ++ net/ipv6/syncookies.c | 2 + 19 files changed, 1159 insertions(+), 12 deletions(-) create mode 100644 net/ipv4/tcp_comp.c -- 1.8.3

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[PATCH kernel-4.19 00/10] tcp compression
by Wang Yufen 01 Aug '21

01 Aug '21

Wang Hai (1): tcp_comp: allow ignore local tcp connections Wang Yufen (6): tcp_comp: add tcp comp option to SYN and SYN-ACK tcp_comp: add init and cleanup hook for compression tcp_comp: only enable compression for give server ports tcp_comp: add stub proto ops for tcp compression socket tcp_comp: implement recvmsg for tcp compression tcp_comp: open configs for tcp compression Wei Yongjun (3): tcp_comp: add Kconfig for tcp payload compression tcp_comp: add sysctl for enable/disable compression tcp_comp: implement sendmsg for tcp compression arch/arm64/configs/hulk_defconfig | 5 +- arch/arm64/configs/openeuler_defconfig | 5 +- arch/x86/configs/hulk_defconfig | 3 + arch/x86/configs/openeuler_defconfig | 5 +- include/linux/tcp.h | 2 +- include/net/inet_sock.h | 3 +- include/net/sock.h | 1 + include/net/tcp.h | 40 ++ net/ipv4/Kconfig | 11 + net/ipv4/Makefile | 1 + net/ipv4/syncookies.c | 2 + net/ipv4/sysctl_net_ipv4.c | 42 ++ net/ipv4/tcp.c | 6 + net/ipv4/tcp_comp.c | 941 +++++++++++++++++++++++++++++++++ net/ipv4/tcp_input.c | 44 +- net/ipv4/tcp_ipv4.c | 2 + net/ipv4/tcp_minisocks.c | 3 + net/ipv4/tcp_output.c | 53 ++ net/ipv6/syncookies.c | 2 + 19 files changed, 1159 insertions(+), 12 deletions(-) create mode 100644 net/ipv4/tcp_comp.c -- 1.8.3

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[PATCH kernel-4.19 1/2] sctp: validate chunk size in __rcv_asconf_lookup
by Yang Yingliang 31 Jul '21

31 Jul '21

From: Marcelo Ricardo Leitner <marcelo.leitner(a)gmail.com> mainline inclusion from mainline-v5.14-rc1 commit b6ffe7671b24689c09faa5675dd58f93758a97ae category: bugfix bugzilla: NA CVE: CVE-2021-3655 --------------------------- In one of the fallbacks that SCTP has for identifying an association for an incoming packet, it looks for AddIp chunk (from ASCONF) and take a peek. Thing is, at this stage nothing was validating that the chunk actually had enough content for that, allowing the peek to happen over uninitialized memory. Similar check already exists in actual asconf handling in sctp_verify_asconf(). Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner(a)gmail.com> Signed-off-by: David S. Miller <davem(a)davemloft.net> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng(a)huawei.com> Reviewed-by: Yue Haibing <yuehaibing(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- net/sctp/input.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/sctp/input.c b/net/sctp/input.c index a2deb36b955a6..3e621582e88b7 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -1125,6 +1125,9 @@ static struct sctp_association *__sctp_rcv_asconf_lookup( union sctp_addr_param *param; union sctp_addr paddr; + if (ntohs(ch->length) < sizeof(*asconf) + sizeof(struct sctp_paramhdr)) + return NULL; + /* Skip over the ADDIP header and find the Address parameter */ param = (union sctp_addr_param *)(asconf + 1); -- 2.25.1

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[PATCH kernel-4.19] stop_machine: Avoid potential race behaviour
by Yang Yingliang 30 Jul '21

30 Jul '21

From: Mark Rutland <mark.rutland(a)arm.com> mainline inclusion from mainline-v5.4-rc4 commit b1fc5833357524d5d342737913dbe32ff3557bc5 category: bugfix bugzilla: 100135 CVE: NA --------------------------- Both multi_cpu_stop() and set_state() access multi_stop_data::state racily using plain accesses. These are subject to compiler transformations which could break the intended behaviour of the code, and this situation is detected by KCSAN on both arm64 and x86 (splats below). Improve matters by using READ_ONCE() and WRITE_ONCE() to ensure that the compiler cannot elide, replay, or tear loads and stores. In multi_cpu_stop() the two loads of multi_stop_data::state are expected to be a consistent value, so snapshot the value into a temporary variable to ensure this. The state transitions are serialized by atomic manipulation of multi_stop_data::num_threads, and other fields in multi_stop_data are not modified while subject to concurrent reads. KCSAN splat on arm64: | BUG: KCSAN: data-race in multi_cpu_stop+0xa8/0x198 and set_state+0x80/0xb0 | | write to 0xffff00001003bd00 of 4 bytes by task 24 on cpu 3: | set_state+0x80/0xb0 | multi_cpu_stop+0x16c/0x198 | cpu_stopper_thread+0x170/0x298 | smpboot_thread_fn+0x40c/0x560 | kthread+0x1a8/0x1b0 | ret_from_fork+0x10/0x18 | | read to 0xffff00001003bd00 of 4 bytes by task 14 on cpu 1: | multi_cpu_stop+0xa8/0x198 | cpu_stopper_thread+0x170/0x298 | smpboot_thread_fn+0x40c/0x560 | kthread+0x1a8/0x1b0 | ret_from_fork+0x10/0x18 | | Reported by Kernel Concurrency Sanitizer on: | CPU: 1 PID: 14 Comm: migration/1 Not tainted 5.3.0-00007-g67ab35a199f4-dirty #3 | Hardware name: linux,dummy-virt (DT) KCSAN splat on x86: | write to 0xffffb0bac0013e18 of 4 bytes by task 19 on cpu 2: | set_state kernel/stop_machine.c:170 [inline] | ack_state kernel/stop_machine.c:177 [inline] | multi_cpu_stop+0x1a4/0x220 kernel/stop_machine.c:227 | cpu_stopper_thread+0x19e/0x280 kernel/stop_machine.c:516 | smpboot_thread_fn+0x1a8/0x300 kernel/smpboot.c:165 | kthread+0x1b5/0x200 kernel/kthread.c:255 | ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:352 | | read to 0xffffb0bac0013e18 of 4 bytes by task 44 on cpu 7: | multi_cpu_stop+0xb4/0x220 kernel/stop_machine.c:213 | cpu_stopper_thread+0x19e/0x280 kernel/stop_machine.c:516 | smpboot_thread_fn+0x1a8/0x300 kernel/smpboot.c:165 | kthread+0x1b5/0x200 kernel/kthread.c:255 | ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:352 | | Reported by Kernel Concurrency Sanitizer on: | CPU: 7 PID: 44 Comm: migration/7 Not tainted 5.3.0+ #1 | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Signed-off-by: Mark Rutland <mark.rutland(a)arm.com> Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de> Acked-by: Marco Elver <elver(a)google.com> Link: https://lkml.kernel.org/r/20191007104536.27276-1-mark.rutland@arm.com Conflicts: kernel/stop_machine.c [yyl: adjust context] Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> Reviewed-by: Jian Cheng <cj.chengjian(a)huawei.com> Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com> --- kernel/stop_machine.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index e0af9b065df82..7e103738f2cca 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -8,6 +8,7 @@ * * This file is released under the GPLv2 and any later version. */ +#include <linux/compiler.h> #include <linux/completion.h> #include <linux/cpu.h> #include <linux/init.h> @@ -173,7 +174,7 @@ static void set_state(struct multi_stop_data *msdata, /* Reset ack counter. */ atomic_set(&msdata->thread_ack, msdata->num_threads); smp_wmb(); - msdata->state = newstate; + WRITE_ONCE(msdata->state, newstate); } /* Last one to ack a state moves to the next state. */ @@ -187,7 +188,7 @@ static void ack_state(struct multi_stop_data *msdata) static int multi_cpu_stop(void *data) { struct multi_stop_data *msdata = data; - enum multi_stop_state curstate = MULTI_STOP_NONE; + enum multi_stop_state newstate, curstate = MULTI_STOP_NONE; int cpu = smp_processor_id(), err = 0; unsigned long flags; bool is_active; @@ -207,8 +208,9 @@ static int multi_cpu_stop(void *data) do { /* Chill out and ensure we re-read multi_stop_state. */ cpu_relax_yield(); - if (msdata->state != curstate) { - curstate = msdata->state; + newstate = READ_ONCE(msdata->state); + if (newstate != curstate) { + curstate = newstate; switch (curstate) { case MULTI_STOP_DISABLE_IRQ: local_irq_disable(); -- 2.25.1

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