kernel/linux.git/net/mac80211/debugfs.c, branch v6.6.132

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable.

2026-03-25T10:06:05+00:00

[ Upstream commit b94ae8e0d5fe1bdbbfdc3854ff6ce98f6876a828 ] syzbot reported static_branch_dec() underflow in aql_enable_write(). [0] The problem is that aql_enable_write() does not serialise concurrent write()s to the debugfs. aql_enable_write() checks static_key_false(&aql_disable.key) and later calls static_branch_inc() or static_branch_dec(), but the state may change between the two calls. aql_disable does not need to track inc/dec. Let's use static_branch_enable() and static_branch_disable(). [0]: val == 0 WARNING: kernel/jump_label.c:311 at __static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311, CPU#0: syz.1.3155/20288 Modules linked in: CPU: 0 UID: 0 PID: 20288 Comm: syz.1.3155 Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:__static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311 Code: f2 c9 ff 5b 5d c3 cc cc cc cc e8 54 f2 c9 ff 48 89 df e8 ac f9 ff ff eb ad e8 45 f2 c9 ff 90 0f 0b 90 eb a2 e8 3a f2 c9 ff 90 <0f> 0b 90 eb 97 48 89 df e8 5c 4b 33 00 e9 36 ff ff ff 0f 1f 80 00 RSP: 0018:ffffc9000b9f7c10 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffffff9b3e5d40 RCX: ffffffff823c57b4 RDX: ffff8880285a0000 RSI: ffffffff823c5846 RDI: ffff8880285a0000 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000a R13: 1ffff9200173ef88 R14: 0000000000000001 R15: ffffc9000b9f7e98 FS: 00007f530dd726c0(0000) GS:ffff8881245e3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001140 CR3: 000000007cc4a000 CR4: 00000000003526f0 Call Trace: __static_key_slow_dec_cpuslocked kernel/jump_label.c:297 [inline] __static_key_slow_dec kernel/jump_label.c:321 [inline] static_key_slow_dec+0x7c/0xc0 kernel/jump_label.c:336 aql_enable_write+0x2b2/0x310 net/mac80211/debugfs.c:343 short_proxy_write+0x133/0x1a0 fs/debugfs/file.c:383 vfs_write+0x2aa/0x1070 fs/read_write.c:684 ksys_pwrite64 fs/read_write.c:793 [inline] __do_sys_pwrite64 fs/read_write.c:801 [inline] __se_sys_pwrite64 fs/read_write.c:798 [inline] __x64_sys_pwrite64+0x1eb/0x250 fs/read_write.c:798 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f530cf9aeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f530dd72028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007f530d215fa0 RCX: 00007f530cf9aeb9 RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000010 RBP: 00007f530d008c1f R08: 0000000000000000 R09: 0000000000000000 R10: 4200000000000005 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f530d216038 R14: 00007f530d215fa0 R15: 00007ffde89fb978 Fixes: e908435e402a ("mac80211: introduce aql_enable node in debugfs") Reported-by: syzbot+feb9ce36a95341bb47a4@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69a8979e.a70a0220.b118c.0025.GAE@google.com/ Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260306072405.3649474-1-kuniyu@google.com Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

wifi: mac80211: remove return value check of debugfs_create_dir()

2023-04-20T09:46:07+00:00

Smatch complains that: debugfs_hw_add() warn: 'statsd' is an error pointer or valid Debugfs checks are generally not supposed to be checked for errors and it is not necessary here. Just delete the dead code. Signed-off-by: Yingsha Xu Reviewed-by: Dongliang Mu Link: https://lore.kernel.org/r/20230419104548.30124-1-ysxu@hust.edu.cn Signed-off-by: Johannes Berg

wifi: mac80211: Drop support for TX push path

2022-10-10T09:06:14+00:00

All drivers are now using mac80211 internal queues (iTXQs). Drop mac80211 internal support for the old push path. Signed-off-by: Alexander Wetzel Signed-off-by: Johannes Berg

wifi: mac80211: optionally implement MLO multicast TX

2022-07-22T12:28:36+00:00

For drivers using software encryption for multicast TX, such as mac80211_hwsim, mac80211 needs to duplicate the multicast frames on each link, if MLO is enabled. Do this, but don't just make it dependent on the key but provide a separate flag for drivers to opt out of this. This is not very efficient, I expect that drivers will do it in firmware/hardware or at least with DMA engine assistence, so this is mostly for hwsim. To make this work, also implement the SNS11 sequence number space that an AP MLD shall have, and modify the API to the __ieee80211_subif_start_xmit() function to always require the link ID bits to be set. Signed-off-by: Johannes Berg

wifi: mac80211: add debugfs file to display per-phy AQL pending airtime

2022-07-01T08:51:48+00:00

Now that the global pending airtime is more relevant for airtime fairness, it makes sense to make it accessible via debugfs for debugging Signed-off-by: Felix Fietkau Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/20220625212411.36675-6-nbd@nbd.name Signed-off-by: Johannes Berg

wifi: mac80211: switch airtime fairness back to deficit round-robin scheduling

2022-07-01T08:51:41+00:00

This reverts commits 6a789ba679d652587532cec2a0e0274fda172f3b and 2433647bc8d983a543e7d31b41ca2de1c7e2c198. The virtual time scheduler code has a number of issues: - queues slowed down by hardware/firmware powersave handling were not properly handled. - on ath10k in push-pull mode, tx queues that the driver tries to pull from were starved, causing excessive latency - delay between tx enqueue and reported airtime use were causing excessively bursty tx behavior The bursty behavior may also be present on the round-robin scheduler, but there it is much easier to fix without introducing additional regressions Signed-off-by: Felix Fietkau Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/20220625212411.36675-1-nbd@nbd.name Signed-off-by: Johannes Berg

mac80211: introduce BSS color collision detection

2022-04-11T13:24:15+00:00

Add ieee80211_rx_check_bss_color_collision routine in order to introduce BSS color collision detection in mac80211 if it is not supported in HW/FW (e.g. for mt7915 chipset). Add IEEE80211_HW_DETECTS_COLOR_COLLISION flag to let the driver notify BSS color collision detection is supported in HW/FW. Set this for ath11k which apparently didn't need this code. Tested-by: Peter Chiu Co-developed-by: Ryder Lee Signed-off-by: Ryder Lee Signed-off-by: Lorenzo Bianconi Link: https://lore.kernel.org/r/a05eeeb1841a84560dc5aaec77894fcb69a54f27.1648204871.git.lorenzo@kernel.org [clarify commit message a bit, move flag to mac80211] Signed-off-by: Johannes Berg

mac80211: remove unused macros

2022-02-04T15:26:27+00:00

Various macros in mac80211 aren't used, remove them. In one case it's used under ifdef, so ifdef it for the W=2 warning. Signed-off-by: Johannes Berg Signed-off-by: Luca Coelho Link: https://lore.kernel.org/r/iwlwifi.20220202104617.5172d7fd878e.I2f1fce686a2b71003f083b2566fb09cf16b8165a@changeid Signed-off-by: Johannes Berg

mac80211: Switch to a virtual time-based airtime scheduler

2021-06-23T16:12:00+00:00

This switches the airtime scheduler in mac80211 to use a virtual time-based scheduler instead of the round-robin scheduler used before. This has a couple of advantages: - No need to sync up the round-robin scheduler in firmware/hardware with the round-robin airtime scheduler. - If several stations are eligible for transmission we can schedule both of them; no need to hard-block the scheduling rotation until the head of the queue has used up its quantum. - The check of whether a station is eligible for transmission becomes simpler (in ieee80211_txq_may_transmit()). The drawback is that scheduling becomes slightly more expensive, as we need to maintain an rbtree of TXQs sorted by virtual time. This means that ieee80211_register_airtime() becomes O(logN) in the number of currently scheduled TXQs because it can change the order of the scheduled stations. We mitigate this overhead by only resorting when a station changes position in the tree, and hopefully N rarely grows too big (it's only TXQs currently backlogged, not all associated stations), so it shouldn't be too big of an issue. To prevent divisions in the fast path, we maintain both station sums and pre-computed reciprocals of the sums. This turns the fast-path operation into a multiplication, with divisions only happening as the number of active stations change (to re-compute the current sum of all active station weights). To prevent this re-computation of the reciprocal from happening too frequently, we use a time-based notion of station activity, instead of updating the weight every time a station gets scheduled or de-scheduled. As queues can oscillate between empty and occupied quite frequently, this can significantly cut down on the number of re-computations. It also has the added benefit of making the station airtime calculation independent on whether the queue happened to have drained at the time an airtime value was accounted. Co-developed-by: Yibo Zhao Signed-off-by: Yibo Zhao Signed-off-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/r/20210623134755.235545-1-toke@redhat.com Signed-off-by: Johannes Berg

mac80211: move interface shutdown out of wiphy lock

2021-06-09T14:09:21+00:00

When reconfiguration fails, we shut down everything, but we cannot call cfg80211_shutdown_all_interfaces() with the wiphy mutex held. Since cfg80211 now calls it on resume errors, we only need to do likewise for where we call reconfig (whether directly or indirectly), but not under the wiphy lock. Cc: stable@vger.kernel.org Fixes: 2fe8ef106238 ("cfg80211: change netdev registration/unregistration semantics") Link: https://lore.kernel.org/r/20210608113226.78233c80f548.Iecc104aceb89f0568f50e9670a9cb191a1c8887b@changeid Signed-off-by: Johannes Berg