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 C1E90364A5; Fri, 24 Nov 2023 19:08:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pohgMJ4c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 526E7C433C7; Fri, 24 Nov 2023 19:08:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700852895; bh=c5SuPHt60Ie9gdF/tbLu3W1eqO6NzjNYi1fFZaK7lz4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pohgMJ4c1SUKDWYnADZejHJohWEG1k5MmUuCiilHKI8Fkc2tnMopcYfdURvB/a7zC nOHiXSU2flt6SVWnSAG1qFXVhKgEOqy2Ls8UnvpzgPSh45rqqWsKqoVKsfJ9/gI9WQ X5csWJe4jA8Zwh/YWHB3EZP3UQA9dG3KcLGJvm4g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Holger Dengler , Harald Freudenberger , Vasily Gorbik Subject: [PATCH 5.10 165/193] s390/ap: fix AP bus crash on early config change callback invocation Date: Fri, 24 Nov 2023 17:54:52 +0000 Message-ID: <20231124171953.792497336@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231124171947.127438872@linuxfoundation.org> References: <20231124171947.127438872@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Harald Freudenberger commit e14aec23025eeb1f2159ba34dbc1458467c4c347 upstream. Fix kernel crash in AP bus code caused by very early invocation of the config change callback function via SCLP. After a fresh IML of the machine the crypto cards are still offline and will get switched online only with activation of any LPAR which has the card in it's configuration. A crypto card coming online is reported to the LPAR via SCLP and the AP bus offers a callback function to get this kind of information. However, it may happen that the callback is invoked before the AP bus init function is complete. As the callback triggers a synchronous AP bus scan, the scan may already run but some internal states are not initialized by the AP bus init function resulting in a crash like this: [ 11.635859] Unable to handle kernel pointer dereference in virtual kernel address space [ 11.635861] Failing address: 0000000000000000 TEID: 0000000000000887 [ 11.635862] Fault in home space mode while using kernel ASCE. [ 11.635864] AS:00000000894c4007 R3:00000001fece8007 S:00000001fece7800 P:000000000000013d [ 11.635879] Oops: 0004 ilc:1 [#1] SMP [ 11.635882] Modules linked in: [ 11.635884] CPU: 5 PID: 42 Comm: kworker/5:0 Not tainted 6.6.0-rc3-00003-g4dbf7cdc6b42 #12 [ 11.635886] Hardware name: IBM 3931 A01 751 (LPAR) [ 11.635887] Workqueue: events_long ap_scan_bus [ 11.635891] Krnl PSW : 0704c00180000000 0000000000000000 (0x0) [ 11.635895] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3 [ 11.635897] Krnl GPRS: 0000000001000a00 0000000000000000 0000000000000006 0000000089591940 [ 11.635899] 0000000080000000 0000000000000a00 0000000000000000 0000000000000000 [ 11.635901] 0000000081870c00 0000000089591000 000000008834e4e2 0000000002625a00 [ 11.635903] 0000000081734200 0000038000913c18 000000008834c6d6 0000038000913ac8 [ 11.635906] Krnl Code:>0000000000000000: 0000 illegal [ 11.635906] 0000000000000002: 0000 illegal [ 11.635906] 0000000000000004: 0000 illegal [ 11.635906] 0000000000000006: 0000 illegal [ 11.635906] 0000000000000008: 0000 illegal [ 11.635906] 000000000000000a: 0000 illegal [ 11.635906] 000000000000000c: 0000 illegal [ 11.635906] 000000000000000e: 0000 illegal [ 11.635915] Call Trace: [ 11.635916] [<0000000000000000>] 0x0 [ 11.635918] [<000000008834e4e2>] ap_queue_init_state+0x82/0xb8 [ 11.635921] [<000000008834ba1c>] ap_scan_domains+0x6fc/0x740 [ 11.635923] [<000000008834c092>] ap_scan_adapter+0x632/0x8b0 [ 11.635925] [<000000008834c3e4>] ap_scan_bus+0xd4/0x288 [ 11.635927] [<00000000879a33ba>] process_one_work+0x19a/0x410 [ 11.635930] Discipline DIAG cannot be used without z/VM [ 11.635930] [<00000000879a3a2c>] worker_thread+0x3fc/0x560 [ 11.635933] [<00000000879aea60>] kthread+0x120/0x128 [ 11.635936] [<000000008792afa4>] __ret_from_fork+0x3c/0x58 [ 11.635938] [<00000000885ebe62>] ret_from_fork+0xa/0x30 [ 11.635942] Last Breaking-Event-Address: [ 11.635942] [<000000008834c6d4>] ap_wait+0xcc/0x148 This patch improves the ap_bus_force_rescan() function which is invoked by the config change callback by checking if a first initial AP bus scan has been done. If not, the force rescan request is simple ignored. Anyhow it does not make sense to trigger AP bus re-scans even before the very first bus scan is complete. Cc: stable@vger.kernel.org Reviewed-by: Holger Dengler Signed-off-by: Harald Freudenberger Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman --- drivers/s390/crypto/ap_bus.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/s390/crypto/ap_bus.c +++ b/drivers/s390/crypto/ap_bus.c @@ -787,6 +787,10 @@ EXPORT_SYMBOL(ap_driver_unregister); void ap_bus_force_rescan(void) { + /* Only trigger AP bus scans after the initial scan is done */ + if (atomic64_read(&ap_scan_bus_count) <= 0) + return; + /* processing a asynchronous bus rescan */ del_timer(&ap_config_timer); queue_work(system_long_wq, &ap_scan_work);