From patchwork Mon Oct 11 20:48:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacob Keller X-Patchwork-Id: 12551037 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9258FC433FE for ; Mon, 11 Oct 2021 20:48:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7797460E8B for ; Mon, 11 Oct 2021 20:48:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235177AbhJKUuj (ORCPT ); Mon, 11 Oct 2021 16:50:39 -0400 Received: from mga06.intel.com ([134.134.136.31]:37914 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235087AbhJKUuj (ORCPT ); Mon, 11 Oct 2021 16:50:39 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10134"; a="287843129" X-IronPort-AV: E=Sophos;i="5.85,365,1624345200"; d="scan'208";a="287843129" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Oct 2021 13:48:37 -0700 X-IronPort-AV: E=Sophos;i="5.85,365,1624345200"; d="scan'208";a="460105429" Received: from jekeller-desk.amr.corp.intel.com ([10.166.244.138]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Oct 2021 13:48:37 -0700 From: Jacob Keller To: netdev@vger.kernel.org Cc: Anthony Nguyen , Jacob Keller Subject: [net PATCH] ice: fix locking for Tx timestamp tracking flush Date: Mon, 11 Oct 2021 13:48:06 -0700 Message-Id: <20211011204806.1504406-1-jacob.e.keller@intel.com> X-Mailer: git-send-email 2.31.1.331.gb0c09ab8796f MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Commit 4dd0d5c33c3e ("ice: add lock around Tx timestamp tracker flush") added a lock around the Tx timestamp tracker flow which is used to cleanup any left over SKBs and prepare for device removal. This lock is problematic because it is being held around a call to ice_clear_phy_tstamp. The clear function takes a mutex to send a PHY write command to firmware. This could lead to a deadlock if the mutex actually sleeps, and causes the following warning on a kernel with preemption debugging enabled: [ 715.419426] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:573 [ 715.427900] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 3100, name: rmmod [ 715.435652] INFO: lockdep is turned off. [ 715.439591] Preemption disabled at: [ 715.439594] [<0000000000000000>] 0x0 [ 715.446678] CPU: 52 PID: 3100 Comm: rmmod Tainted: G W OE 5.15.0-rc4+ #42 bdd7ec3018e725f159ca0d372ce8c2c0e784891c [ 715.458058] Hardware name: Intel Corporation S2600STQ/S2600STQ, BIOS SE5C620.86B.02.01.0010.010620200716 01/06/2020 [ 715.468483] Call Trace: [ 715.470940] dump_stack_lvl+0x6a/0x9a [ 715.474613] ___might_sleep.cold+0x224/0x26a [ 715.478895] __mutex_lock+0xb3/0x1440 [ 715.482569] ? stack_depot_save+0x378/0x500 [ 715.486763] ? ice_sq_send_cmd+0x78/0x14c0 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.494979] ? kfree+0xc1/0x520 [ 715.498128] ? mutex_lock_io_nested+0x12a0/0x12a0 [ 715.502837] ? kasan_set_free_info+0x20/0x30 [ 715.507110] ? __kasan_slab_free+0x10b/0x140 [ 715.511385] ? slab_free_freelist_hook+0xc7/0x220 [ 715.516092] ? kfree+0xc1/0x520 [ 715.519235] ? ice_deinit_lag+0x16c/0x220 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.527359] ? ice_remove+0x1cf/0x6a0 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.535133] ? pci_device_remove+0xab/0x1d0 [ 715.539318] ? __device_release_driver+0x35b/0x690 [ 715.544110] ? driver_detach+0x214/0x2f0 [ 715.548035] ? bus_remove_driver+0x11d/0x2f0 [ 715.552309] ? pci_unregister_driver+0x26/0x250 [ 715.556840] ? ice_module_exit+0xc/0x2f [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.564799] ? __do_sys_delete_module.constprop.0+0x2d8/0x4e0 [ 715.570554] ? do_syscall_64+0x3b/0x90 [ 715.574303] ? entry_SYSCALL_64_after_hwframe+0x44/0xae [ 715.579529] ? start_flush_work+0x542/0x8f0 [ 715.583719] ? ice_sq_send_cmd+0x78/0x14c0 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.591923] ice_sq_send_cmd+0x78/0x14c0 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.599960] ? wait_for_completion_io+0x250/0x250 [ 715.604662] ? lock_acquire+0x196/0x200 [ 715.608504] ? do_raw_spin_trylock+0xa5/0x160 [ 715.612864] ice_sbq_rw_reg+0x1e6/0x2f0 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.620813] ? ice_reset+0x130/0x130 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.628497] ? __debug_check_no_obj_freed+0x1e8/0x3c0 [ 715.633550] ? trace_hardirqs_on+0x1c/0x130 [ 715.637748] ice_write_phy_reg_e810+0x70/0xf0 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.646220] ? do_raw_spin_trylock+0xa5/0x160 [ 715.650581] ? ice_ptp_release+0x910/0x910 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.658797] ? ice_ptp_release+0x255/0x910 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.667013] ice_clear_phy_tstamp+0x2c/0x110 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.675403] ice_ptp_release+0x408/0x910 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.683440] ice_remove+0x560/0x6a0 [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.691037] ? _raw_spin_unlock_irqrestore+0x46/0x73 [ 715.696005] pci_device_remove+0xab/0x1d0 [ 715.700018] __device_release_driver+0x35b/0x690 [ 715.704637] driver_detach+0x214/0x2f0 [ 715.708389] bus_remove_driver+0x11d/0x2f0 [ 715.712489] pci_unregister_driver+0x26/0x250 [ 715.716857] ice_module_exit+0xc/0x2f [ice 9a7e1ec00971c89ecd3fe0d4dc7da2b3786a421d] [ 715.724637] __do_sys_delete_module.constprop.0+0x2d8/0x4e0 [ 715.730210] ? free_module+0x6d0/0x6d0 [ 715.733963] ? task_work_run+0xe1/0x170 [ 715.737803] ? exit_to_user_mode_loop+0x17f/0x1d0 [ 715.742509] ? rcu_read_lock_sched_held+0x12/0x80 [ 715.747215] ? trace_hardirqs_on+0x1c/0x130 [ 715.751401] do_syscall_64+0x3b/0x90 [ 715.754981] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 715.760033] RIP: 0033:0x7f4dfe59000b [ 715.763612] Code: 73 01 c3 48 8b 0d 6d 1e 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 3d 1e 0c 00 f7 d8 64 89 01 48 [ 715.782357] RSP: 002b:00007ffe8c891708 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 [ 715.789923] RAX: ffffffffffffffda RBX: 00005558a20468b0 RCX: 00007f4dfe59000b [ 715.797054] RDX: 000000000000000a RSI: 0000000000000800 RDI: 00005558a2046918 [ 715.804189] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 715.811319] R10: 00007f4dfe603ac0 R11: 0000000000000206 R12: 00007ffe8c891940 [ 715.818455] R13: 00007ffe8c8920a3 R14: 00005558a20462a0 R15: 00005558a20468b0 Notice that this is the only case where we use the lock in this way. In the cleanup kthread and work kthread the lock is only taken around the bit accesses. This was done intentionally to avoid this kind of issue. The way the lock is used, we only protect ordering of bit sets vs bit clears. The Tx writers in the hot path don't need to be protected against the entire kthread loop. The Tx queues threads only need to ensure that they do not re-use an index that is currently in use. The cleanup loop does not need to block all new set bits, since it will re-queue itself if new timestamps are present. Fix the tracker flow so that it uses the same flow as the standard cleanup thread. In addition, ensure the in_use bitmap actually gets cleared properly. This fixes the warning and also avoids the potential deadlock that might have occurred otherwise. Fixes: 4dd0d5c33c3e ("ice: add lock around Tx timestamp tracker flush") Signed-off-by: Jacob Keller Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/ice/ice_ptp.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) base-commit: 732b74d647048668f0f8dc0c848f0746c69e2e2f diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c index 05cc5870e4ef..80380aed8882 100644 --- a/drivers/net/ethernet/intel/ice/ice_ptp.c +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c @@ -1313,22 +1313,21 @@ ice_ptp_flush_tx_tracker(struct ice_pf *pf, struct ice_ptp_tx *tx) { u8 idx; - spin_lock(&tx->lock); - for (idx = 0; idx < tx->len; idx++) { u8 phy_idx = idx + tx->quad_offset; - /* Clear any potential residual timestamp in the PHY block */ - if (!pf->hw.reset_ongoing) - ice_clear_phy_tstamp(&pf->hw, tx->quad, phy_idx); - + spin_lock(&tx->lock); if (tx->tstamps[idx].skb) { dev_kfree_skb_any(tx->tstamps[idx].skb); tx->tstamps[idx].skb = NULL; } - } + clear_bit(idx, tx->in_use); + spin_unlock(&tx->lock); - spin_unlock(&tx->lock); + /* Clear any potential residual timestamp in the PHY block */ + if (!pf->hw.reset_ongoing) + ice_clear_phy_tstamp(&pf->hw, tx->quad, phy_idx); + } } /**