kernel.git/net/sched/sch_api.c, branch linux-5.16.y

net_sched: add __rcu annotation to netdev->qdisc

2022-02-23T11:05:57Z

commit 5891cd5ec46c2c2eb6427cb54d214b149635dd0e upstream. syzbot found a data-race [1] which lead me to add __rcu annotations to netdev->qdisc, and proper accessors to get LOCKDEP support. [1] BUG: KCSAN: data-race in dev_activate / qdisc_lookup_rcu write to 0xffff888168ad6410 of 8 bytes by task 13559 on cpu 1: attach_default_qdiscs net/sched/sch_generic.c:1167 [inline] dev_activate+0x2ed/0x8f0 net/sched/sch_generic.c:1221 __dev_open+0x2e9/0x3a0 net/core/dev.c:1416 __dev_change_flags+0x167/0x3f0 net/core/dev.c:8139 rtnl_configure_link+0xc2/0x150 net/core/rtnetlink.c:3150 __rtnl_newlink net/core/rtnetlink.c:3489 [inline] rtnl_newlink+0xf4d/0x13e0 net/core/rtnetlink.c:3529 rtnetlink_rcv_msg+0x745/0x7e0 net/core/rtnetlink.c:5594 netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2494 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5612 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x602/0x6d0 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x728/0x850 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2413 ___sys_sendmsg net/socket.c:2467 [inline] __sys_sendmsg+0x195/0x230 net/socket.c:2496 __do_sys_sendmsg net/socket.c:2505 [inline] __se_sys_sendmsg net/socket.c:2503 [inline] __x64_sys_sendmsg+0x42/0x50 net/socket.c:2503 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff888168ad6410 of 8 bytes by task 13560 on cpu 0: qdisc_lookup_rcu+0x30/0x2e0 net/sched/sch_api.c:323 __tcf_qdisc_find+0x74/0x3a0 net/sched/cls_api.c:1050 tc_del_tfilter+0x1c7/0x1350 net/sched/cls_api.c:2211 rtnetlink_rcv_msg+0x5ba/0x7e0 net/core/rtnetlink.c:5585 netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2494 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5612 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x602/0x6d0 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x728/0x850 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2413 ___sys_sendmsg net/socket.c:2467 [inline] __sys_sendmsg+0x195/0x230 net/socket.c:2496 __do_sys_sendmsg net/socket.c:2505 [inline] __se_sys_sendmsg net/socket.c:2503 [inline] __x64_sys_sendmsg+0x42/0x50 net/socket.c:2503 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0xffffffff85dee080 -> 0xffff88815d96ec00 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 13560 Comm: syz-executor.2 Not tainted 5.17.0-rc3-syzkaller-00116-gf1baf68e1383-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 470502de5bdb ("net: sched: unlock rules update API") Signed-off-by: Eric Dumazet Cc: Vlad Buslov Reported-by: syzbot Cc: Jamal Hadi Salim Cc: Cong Wang Cc: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sched: Clarify error message when qdisc kind is unknown

2022-02-16T11:58:13Z

[ Upstream commit 973bf8fdd12f0e70ea351c018e68edd377a836d1 ] When adding a tc rule with a qdisc kind that is not supported or not compiled into the kernel, the kernel emits the following error: "Error: Specified qdisc not found.". Found via tdc testing when ETS qdisc was not compiled in and it was not obvious right away what the message meant without looking at the kernel code. Change the error message to be more explicit and say the qdisc kind is unknown. Signed-off-by: Victor Nogueira Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

sch_api: Don't skip qdisc attach on ingress

2022-01-27T11:03:03Z

commit de2d807b294d3d2ce5e59043ae2634016765d076 upstream. The attach callback of struct Qdisc_ops is used by only a few qdiscs: mq, mqprio and htb. qdisc_graft() contains the following logic (pseudocode): if (!qdisc->ops->attach) { if (ingress) do ingress stuff; else do egress stuff; } if (!ingress) { ... if (qdisc->ops->attach) qdisc->ops->attach(qdisc); } else { ... } As we see, the attach callback is not called if the qdisc is being attached to ingress (TC_H_INGRESS). That wasn't a problem for mq and mqprio, since they contain a check that they are attached to TC_H_ROOT, and they can't be attached to TC_H_INGRESS anyway. However, the commit cited below added the attach callback to htb. It is needed for the hardware offload, but in the non-offload mode it simulates the "do egress stuff" part of the pseudocode above. The problem is that when htb is attached to ingress, neither "do ingress stuff" nor attach() is called. It results in an inconsistency, and the following message is printed to dmesg: unregister_netdevice: waiting for lo to become free. Usage count = 2 This commit addresses the issue by running "do ingress stuff" in the ingress flow even in the attach callback is present, which is fine, because attach isn't going to be called afterwards. The bug was found by syzbot and reported by Eric. Fixes: d03b195b5aa0 ("sch_htb: Hierarchical QoS hardware offload") Signed-off-by: Maxim Mikityanskiy Reported-by: Eric Dumazet Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sched: Remove Qdisc::running sequence counter

2021-10-18T11:54:41Z

The Qdisc::running sequence counter has two uses: 1. Reliably reading qdisc's tc statistics while the qdisc is running (a seqcount read/retry loop at gnet_stats_add_basic()). 2. As a flag, indicating whether the qdisc in question is running (without any retry loops). For the first usage, the Qdisc::running sequence counter write section, qdisc_run_begin() => qdisc_run_end(), covers a much wider area than what is actually needed: the raw qdisc's bstats update. A u64_stats sync point was thus introduced (in previous commits) inside the bstats structure itself. A local u64_stats write section is then started and stopped for the bstats updates. Use that u64_stats sync point mechanism for the bstats read/retry loop at gnet_stats_add_basic(). For the second qdisc->running usage, a __QDISC_STATE_RUNNING bit flag, accessed with atomic bitops, is sufficient. Using a bit flag instead of a sequence counter at qdisc_run_begin/end() and qdisc_is_running() leads to the SMP barriers implicitly added through raw_read_seqcount() and write_seqcount_begin/end() getting removed. All call sites have been surveyed though, and no required ordering was identified. Now that the qdisc->running sequence counter is no longer used, remove it. Note, using u64_stats implies no sequence counter protection for 64-bit architectures. This can lead to the qdisc tc statistics "packets" vs. "bytes" values getting out of sync on rare occasions. The individual values will still be valid. Signed-off-by: Ahmed S. Darwish Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: David S. Miller

net: sched: Merge Qdisc::bstats and Qdisc::cpu_bstats data types

2021-10-18T11:54:41Z

The only factor differentiating per-CPU bstats data type (struct gnet_stats_basic_cpu) from the packed non-per-CPU one (struct gnet_stats_basic_packed) was a u64_stats sync point inside the former. The two data types are now equivalent: earlier commits added a u64_stats sync point to the latter. Combine both data types into "struct gnet_stats_basic_sync". This eliminates redundancy and simplifies the bstats read/write APIs. Use u64_stats_t for bstats "packets" and "bytes" data types. On 64-bit architectures, u64_stats sync points do not use sequence counter protection. Signed-off-by: Ahmed S. Darwish Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: David S. Miller

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

2021-09-30T21:49:21Z

drivers/net/phy/bcm7xxx.c d88fd1b546ff ("net: phy: bcm7xxx: Fixed indirect MMD operations") f68d08c437f9 ("net: phy: bcm7xxx: Add EPHY entry for 72165") net/sched/sch_api.c b193e15ac69d ("net: prevent user from passing illegal stab size") 69508d43334e ("net_sched: Use struct_size() and flex_array_size() helpers") Both cases trivial - adjacent code additions. Signed-off-by: Jakub Kicinski

net_sched: Use struct_size() and flex_array_size() helpers

2021-09-30T01:56:53Z

Make use of the struct_size() and flex_array_size() helpers instead of an open-coded version, in order to avoid any potential type mistakes or integer overflows that, in the worse scenario, could lead to heap overflows. Link: https://github.com/KSPP/linux/issues/160 Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20210928193107.GA262595@embeddedor Signed-off-by: Jakub Kicinski

net: prevent user from passing illegal stab size

2021-09-26T10:09:07Z

We observed below report when playing with netlink sock: UBSAN: shift-out-of-bounds in net/sched/sch_api.c:580:10 shift exponent 249 is too large for 32-bit type CPU: 0 PID: 685 Comm: a.out Not tainted Call Trace: dump_stack_lvl+0x8d/0xcf ubsan_epilogue+0xa/0x4e __ubsan_handle_shift_out_of_bounds+0x161/0x182 __qdisc_calculate_pkt_len+0xf0/0x190 __dev_queue_xmit+0x2ed/0x15b0 it seems like kernel won't check the stab log value passing from user, and will use the insane value later to calculate pkt_len. This patch just add a check on the size/cell_log to avoid insane calculation. Reported-by: Abaci Signed-off-by: Michael Wang Signed-off-by: David S. Miller

net/sched: Remove unnecessary if statement

2021-07-16T17:46:35Z

It has been deal with the 'if (err' statement in rtnetlink_send() and rtnl_unicast(). so remove unnecessary if statement. v2: use the raw name rtnetlink_send(). Signed-off-by: Yajun Deng Signed-off-by: David S. Miller

net: sched: avoid duplicates in classes dump

2021-03-04T22:27:47Z

This is a follow up of commit ea3274695353 ("net: sched: avoid duplicates in qdisc dump") which has fixed the issue only for the qdisc dump. The duplicate printing also occurs when dumping the classes via tc class show dev eth0 Fixes: 59cc1f61f09c ("net: sched: convert qdisc linked list to hashtable") Signed-off-by: Maximilian Heyne Signed-off-by: David S. Miller