From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 379151875 for ; Wed, 28 Dec 2022 15:58:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2207C433D2; Wed, 28 Dec 2022 15:58:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672243103; bh=NxM83+USHhwwxGcBp16Ts/UMl6kRvcItqMXZWctqbNw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MYl8MXVRojQll4pSuLxcfi7O3zJU1L9+Sp/uTH5YMm1LdwQ7a3nn/SNqSQcfndYHF hMGoe208KT1WY2c0O07MIaX978pzPsJzSCrFOpGwZAysvLWHcFMjPT1+IxAbuTwbXp Fns4ty9VyaWx7piWUAdBhbs9Y1kYjIfTlQ+z2ZhM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Justin Tee , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 5.15 675/731] scsi: lpfc: Fix hard lockup when reading the rx_monitor from debugfs Date: Wed, 28 Dec 2022 15:43:02 +0100 Message-Id: <20221228144316.043176344@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144256.536395940@linuxfoundation.org> References: <20221228144256.536395940@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Justin Tee [ Upstream commit c44e50f4a0ec00c2298f31f91bc2c3e9bbd81c7e ] During I/O and simultaneous cat of /sys/kernel/debug/lpfc/fnX/rx_monitor, a hard lockup similar to the call trace below may occur. The spin_lock_bh in lpfc_rx_monitor_report is not protecting from timer interrupts as expected, so change the strength of the spin lock to _irq. Kernel panic - not syncing: Hard LOCKUP CPU: 3 PID: 110402 Comm: cat Kdump: loaded exception RIP: native_queued_spin_lock_slowpath+91 [IRQ stack] native_queued_spin_lock_slowpath at ffffffffb814e30b _raw_spin_lock at ffffffffb89a667a lpfc_rx_monitor_record at ffffffffc0a73a36 [lpfc] lpfc_cmf_timer at ffffffffc0abbc67 [lpfc] __hrtimer_run_queues at ffffffffb8184250 hrtimer_interrupt at ffffffffb8184ab0 smp_apic_timer_interrupt at ffffffffb8a026ba apic_timer_interrupt at ffffffffb8a01c4f [End of IRQ stack] apic_timer_interrupt at ffffffffb8a01c4f lpfc_rx_monitor_report at ffffffffc0a73c80 [lpfc] lpfc_rx_monitor_read at ffffffffc0addde1 [lpfc] full_proxy_read at ffffffffb83e7fc3 vfs_read at ffffffffb833fe71 ksys_read at ffffffffb83402af do_syscall_64 at ffffffffb800430b entry_SYSCALL_64_after_hwframe at ffffffffb8a000ad Signed-off-by: Justin Tee Link: https://lore.kernel.org/r/20221017164323.14536-2-justintee8345@gmail.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/lpfc/lpfc_sli.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c index d6e761adf1f1..df3b190fccd1 100644 --- a/drivers/scsi/lpfc/lpfc_sli.c +++ b/drivers/scsi/lpfc/lpfc_sli.c @@ -7992,10 +7992,10 @@ u32 lpfc_rx_monitor_report(struct lpfc_hba *phba, "IO_cnt", "Info", "BWutil(ms)"); } - /* Needs to be _bh because record is called from timer interrupt + /* Needs to be _irq because record is called from timer interrupt * context */ - spin_lock_bh(ring_lock); + spin_lock_irq(ring_lock); while (*head_idx != *tail_idx) { entry = &ring[*head_idx]; @@ -8039,7 +8039,7 @@ u32 lpfc_rx_monitor_report(struct lpfc_hba *phba, if (cnt >= max_read_entries) break; } - spin_unlock_bh(ring_lock); + spin_unlock_irq(ring_lock); return cnt; } -- 2.35.1