kernel.git/net/rds/tcp.c, branch linux-rolling-stable

net/rds: Fix circular locking dependency in rds_tcp_tune

2026-03-12T11:09:51Z

[ Upstream commit 6a877ececd6daa002a9a0002cd0fbca6592a9244 ] syzbot reported a circular locking dependency in rds_tcp_tune() where sk_net_refcnt_upgrade() is called while holding the socket lock: ====================================================== WARNING: possible circular locking dependency detected ====================================================== kworker/u10:8/15040 is trying to acquire lock: ffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_cache_noprof+0x4b/0x6f0 but task is already holding lock: ffff88805a3c1ce0 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: rds_tcp_tune+0xd7/0x930 The issue occurs because sk_net_refcnt_upgrade() performs memory allocation (via get_net_track() -> ref_tracker_alloc()) while the socket lock is held, creating a circular dependency with fs_reclaim. Fix this by moving sk_net_refcnt_upgrade() outside the socket lock critical section. This is safe because the fields modified by the sk_net_refcnt_upgrade() call (sk_net_refcnt, ns_tracker) are not accessed by any concurrent code path at this point. v2: - Corrected fixes tag - check patch line wrap nits - ai commentary nits Reported-by: syzbot+2e2cf5331207053b8106@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2e2cf5331207053b8106 Fixes: 3a58f13a881e ("net: rds: acquire refcount on TCP sockets") Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260227202336.167757-1-achender@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: better track kernel sockets lifetime

2025-02-22T00:00:58Z

While kernel sockets are dismantled during pernet_operations->exit(), their freeing can be delayed by any tx packets still held in qdisc or device queues, due to skb_set_owner_w() prior calls. This then trigger the following warning from ref_tracker_dir_exit() [1] To fix this, make sure that kernel sockets own a reference on net->passive. Add sk_net_refcnt_upgrade() helper, used whenever a kernel socket is converted to a refcounted one. [1] [ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at [ 136.263918][ T35] sk_alloc+0x2b3/0x370 [ 136.263918][ T35] inet6_create+0x6ce/0x10f0 [ 136.263918][ T35] __sock_create+0x4c0/0xa30 [ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250 [ 136.263918][ T35] igmp6_net_init+0x39/0x390 [ 136.263918][ T35] ops_init+0x31e/0x590 [ 136.263918][ T35] setup_net+0x287/0x9e0 [ 136.263918][ T35] copy_net_ns+0x33f/0x570 [ 136.263918][ T35] create_new_namespaces+0x425/0x7b0 [ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180 [ 136.263918][ T35] ksys_unshare+0x57d/0xa70 [ 136.263918][ T35] __x64_sys_unshare+0x38/0x40 [ 136.263918][ T35] do_syscall_64+0xf3/0x230 [ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 136.263918][ T35] [ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at [ 136.343488][ T35] sk_alloc+0x2b3/0x370 [ 136.343488][ T35] inet6_create+0x6ce/0x10f0 [ 136.343488][ T35] __sock_create+0x4c0/0xa30 [ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250 [ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0 [ 136.343488][ T35] ops_init+0x31e/0x590 [ 136.343488][ T35] setup_net+0x287/0x9e0 [ 136.343488][ T35] copy_net_ns+0x33f/0x570 [ 136.343488][ T35] create_new_namespaces+0x425/0x7b0 [ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180 [ 136.343488][ T35] ksys_unshare+0x57d/0xa70 [ 136.343488][ T35] __x64_sys_unshare+0x38/0x40 [ 136.343488][ T35] do_syscall_64+0xf3/0x230 [ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 0cafd77dcd03 ("net: add a refcount tracker for kernel sockets") Reported-by: syzbot+30a19e01a97420719891@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/67b72aeb.050a0220.14d86d.0283.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250220131854.4048077-1-edumazet@google.com Signed-off-by: Jakub Kicinski

rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy

2025-01-09T16:53:35Z

As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons: - Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns. - current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2). The per-netns structure can be obtained from the table->data using container_of(), then the 'net' one can be retrieved from the listen socket (if available). Fixes: c6a58ffed536 ("RDS: TCP: Add sysctl tunables for sndbuf/rcvbuf on rds-tcp socket") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/67769ecb.050a0220.3a8527.003f.GAE@google.com [1] Suggested-by: Al Viro Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250108-net-sysctl-current-nsproxy-v1-9-5df34b2083e8@kernel.org Signed-off-by: Jakub Kicinski

sysctl: treewide: constify the ctl_table argument of proc_handlers

2024-07-24T18:59:29Z

const qualify the struct ctl_table argument in the proc_handler function signatures. This is a prerequisite to moving the static ctl_table structs into .rodata data which will ensure that proc_handler function pointers cannot be modified. This patch has been generated by the following coccinelle script: ``` virtual patch @r1@ identifier ctl, write, buffer, lenp, ppos; identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)"; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos); @r2@ identifier func, ctl, write, buffer, lenp, ppos; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos) { ... } @r3@ identifier func; @@ int func( - struct ctl_table * + const struct ctl_table * ,int , void *, size_t *, loff_t *); @r4@ identifier func, ctl; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int , void *, size_t *, loff_t *); @r5@ identifier func, write, buffer, lenp, ppos; @@ int func( - struct ctl_table * + const struct ctl_table * ,int write, void *buffer, size_t *lenp, loff_t *ppos); ``` * Code formatting was adjusted in xfs_sysctl.c to comply with code conventions. The xfs_stats_clear_proc_handler, xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where adjusted. * The ctl_table argument in proc_watchdog_common was const qualified. This is called from a proc_handler itself and is calling back into another proc_handler, making it necessary to change it as part of the proc_handler migration. Co-developed-by: Thomas Weißschuh Signed-off-by: Thomas Weißschuh Co-developed-by: Joel Granados Signed-off-by: Joel Granados

rds:Simplify the allocation of slab caches

2024-06-19T09:47:40Z

Use the new KMEM_CACHE() macro instead of direct kmem_cache_create to simplify the creation of SLAB caches. Signed-off-by: Hongfu Li Reviewed-by: Zhu Yanjun Reviewed-by: Allison Henderson Signed-off-by: David S. Miller

net: rds: Remove the now superfluous sentinel elements from ctl_table array

2024-05-03T12:29:42Z

This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) * Remove sentinel element from ctl_table structs. Signed-off-by: Joel Granados Acked-by: Allison Henderson Signed-off-by: David S. Miller

networking: Update to register_net_sysctl_sz

2023-08-15T22:26:18Z

Move from register_net_sysctl to register_net_sysctl_sz for all the networking related files. Do this while making sure to mirror the NULL assignments with a table_size of zero for the unprivileged users. We need to move to the new function in preparation for when we change SIZE_MAX to ARRAY_SIZE() in the register_net_sysctl macro. Failing to do so would erroneously allow ARRAY_SIZE() to be called on a pointer. We hold off the SIZE_MAX to ARRAY_SIZE change until we have migrated all the relevant net sysctl registering functions to register_net_sysctl_sz in subsequent commits. An additional size function was added to the following files in order to calculate the size of an array that is defined in another file: include/net/ipv6.h net/ipv6/icmp.c net/ipv6/route.c net/ipv6/sysctl_net_ipv6.c Signed-off-by: Joel Granados Signed-off-by: Luis Chamberlain

net: add a refcount tracker for kernel sockets

2022-10-24T10:04:43Z

Commit ffa84b5ffb37 ("net: add netns refcount tracker to struct sock") added a tracker to sockets, but did not track kernel sockets. We still have syzbot reports hinting about netns being destroyed while some kernel TCP sockets had not been dismantled. This patch tracks kernel sockets, and adds a ref_tracker_dir_print() call to net_free() right before the netns is freed. Normally, each layer is responsible for properly releasing its kernel sockets before last call to net_free(). This debugging facility is enabled with CONFIG_NET_NS_REFCNT_TRACKER=y Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Tested-by: Kuniyuki Iwashima Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2022-10-04T00:44:18Z

Merge in the left-over fixes before the net-next pull-request. Conflicts: drivers/net/ethernet/mediatek/mtk_ppe.c ae3ed15da588 ("net: ethernet: mtk_eth_soc: fix state in __mtk_foe_entry_clear") 9d8cb4c096ab ("net: ethernet: mtk_eth_soc: add foe_entry_size to mtk_eth_soc") https://lore.kernel.org/all/6cb6893b-4921-a068-4c30-1109795110bb@tessares.net/ kernel/bpf/helpers.c 8addbfc7b308 ("bpf: Gate dynptr API behind CAP_BPF") 5679ff2f138f ("bpf: Move bpf_loop and bpf_for_each_map_elem under CAP_BPF") 8a67f2de9b1d ("bpf: expose bpf_strtol and bpf_strtoul to all program types") https://lore.kernel.org/all/20221003201957.13149-1-daniel@iogearbox.net/ Signed-off-by: Jakub Kicinski

net: rds: don't hold sock lock when cancelling work from rds_tcp_reset_callbacks()

2022-10-03T06:56:02Z

syzbot is reporting lockdep warning at rds_tcp_reset_callbacks() [1], for commit ac3615e7f3cffe2a ("RDS: TCP: Reduce code duplication in rds_tcp_reset_callbacks()") added cancel_delayed_work_sync() into a section protected by lock_sock() without realizing that rds_send_xmit() might call lock_sock(). We don't need to protect cancel_delayed_work_sync() using lock_sock(), for even if rds_{send,recv}_worker() re-queued this work while __flush_work() from cancel_delayed_work_sync() was waiting for this work to complete, retried rds_{send,recv}_worker() is no-op due to the absence of RDS_CONN_UP bit. Link: https://syzkaller.appspot.com/bug?extid=78c55c7bc6f66e53dce2 [1] Reported-by: syzbot Co-developed-by: Hillf Danton Signed-off-by: Hillf Danton Signed-off-by: Tetsuo Handa Tested-by: syzbot Fixes: ac3615e7f3cffe2a ("RDS: TCP: Reduce code duplication in rds_tcp_reset_callbacks()") Signed-off-by: David S. Miller