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 AE6811ED38 for ; Tue, 25 Jul 2023 11:30:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 26858C433C7; Tue, 25 Jul 2023 11:30:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690284629; bh=n94wn2fRCgx71sDS1DsBOFCyDTiChA3lMIo+hAjQ6b8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fbL7lrzTCuokzSlGUupHpT2YDQ2Btz8fTa4D44JblrnK14x67HPsLlTFp/W8LquBW 94MxrzxlKZoAb6gJrPZCE7OI9FOAH/RRHAbIiAhZAmWWYhS8D+62ms57EjMJvDS/C8 ryCqZc9ReYVbr3GBaGgMGZ5qCpXoEE7NhulNcQFs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Krister Johansen , Leon Romanovsky , Shay Agroskin , Jakub Kicinski Subject: [PATCH 5.10 424/509] net: ena: fix shift-out-of-bounds in exponential backoff Date: Tue, 25 Jul 2023 12:46:03 +0200 Message-ID: <20230725104613.091731741@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230725104553.588743331@linuxfoundation.org> References: <20230725104553.588743331@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: Krister Johansen commit 1e9cb763e9bacf0c932aa948f50dcfca6f519a26 upstream. The ENA adapters on our instances occasionally reset. Once recently logged a UBSAN failure to console in the process: UBSAN: shift-out-of-bounds in build/linux/drivers/net/ethernet/amazon/ena/ena_com.c:540:13 shift exponent 32 is too large for 32-bit type 'unsigned int' CPU: 28 PID: 70012 Comm: kworker/u72:2 Kdump: loaded not tainted 5.15.117 Hardware name: Amazon EC2 c5d.9xlarge/, BIOS 1.0 10/16/2017 Workqueue: ena ena_fw_reset_device [ena] Call Trace: dump_stack_lvl+0x4a/0x63 dump_stack+0x10/0x16 ubsan_epilogue+0x9/0x36 __ubsan_handle_shift_out_of_bounds.cold+0x61/0x10e ? __const_udelay+0x43/0x50 ena_delay_exponential_backoff_us.cold+0x16/0x1e [ena] wait_for_reset_state+0x54/0xa0 [ena] ena_com_dev_reset+0xc8/0x110 [ena] ena_down+0x3fe/0x480 [ena] ena_destroy_device+0xeb/0xf0 [ena] ena_fw_reset_device+0x30/0x50 [ena] process_one_work+0x22b/0x3d0 worker_thread+0x4d/0x3f0 ? process_one_work+0x3d0/0x3d0 kthread+0x12a/0x150 ? set_kthread_struct+0x50/0x50 ret_from_fork+0x22/0x30 Apparently, the reset delays are getting so large they can trigger a UBSAN panic. Looking at the code, the current timeout is capped at 5000us. Using a base value of 100us, the current code will overflow after (1<<29). Even at values before 32, this function wraps around, perhaps unintentionally. Cap the value of the exponent used for this backoff at (1<<16) which is larger than currently necessary, but large enough to support bigger values in the future. Cc: stable@vger.kernel.org Fixes: 4bb7f4cf60e3 ("net: ena: reduce driver load time") Signed-off-by: Krister Johansen Reviewed-by: Leon Romanovsky Reviewed-by: Shay Agroskin Link: https://lore.kernel.org/r/20230711013621.GE1926@templeofstupid.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/amazon/ena/ena_com.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/net/ethernet/amazon/ena/ena_com.c +++ b/drivers/net/ethernet/amazon/ena/ena_com.c @@ -35,6 +35,8 @@ #define ENA_REGS_ADMIN_INTR_MASK 1 +#define ENA_MAX_BACKOFF_DELAY_EXP 16U + #define ENA_MIN_ADMIN_POLL_US 100 #define ENA_MAX_ADMIN_POLL_US 5000 @@ -522,6 +524,7 @@ static int ena_com_comp_status_to_errno( static void ena_delay_exponential_backoff_us(u32 exp, u32 delay_us) { + exp = min_t(u32, exp, ENA_MAX_BACKOFF_DELAY_EXP); delay_us = max_t(u32, ENA_MIN_ADMIN_POLL_US, delay_us); delay_us = min_t(u32, delay_us * (1U << exp), ENA_MAX_ADMIN_POLL_US); usleep_range(delay_us, 2 * delay_us);