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From:   Luis Chamberlain <mcgrof@kernel.org>
To:     jeyu@kernel.org
Cc:     akpm@linux-foundation.org, arnd@arndb.de, rostedt@goodmis.org,
        mingo@redhat.com, aquini@redhat.com, cai@lca.pw, dyoung@redhat.com,
        bhe@redhat.com, peterz@infradead.org, tglx@linutronix.de,
        gpiccoli@canonical.com, pmladek@suse.com, tiwai@suse.de,
        schlad@suse.de, andriy.shevchenko@linux.intel.com,
        keescook@chromium.org, daniel.vetter@ffwll.ch, will@kernel.org,
        mchehab+samsung@kernel.org, kvalo@codeaurora.org,
        davem@davemloft.net, linux-kernel@vger.kernel.org,
        Luis Chamberlain <mcgrof@kernel.org>
Subject: [RFC] taint: add module firmware crash taint support
Date:   Fri,  8 May 2020 02:14:38 +0000
Message-Id: <20200508021438.4373-1-mcgrof@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Device driver firmware can crash, and sometimes, this can leave your
system in a state which makes the device or subsystem completely
useless. Detecting this by inspecting /proc/sys/kernel/tainted instead
of scraping some magical words from the kernel log, which is driver
specific, is much easier. So instead provide a helper which lets drivers
annotate this.

Once this happens, scrapers can easily scrape modules taint flags.
This will taint both the kernel and respective calling module.

The new helper module_firmware_crashed() uses LOCKDEP_STILL_OK as
this fact should in no way shape or form affect lockdep. This taint
is device driver specific.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---

Below is the full diff stat of manual inspection throughout the kernel
when this happens. My methodology is to just scrape for "crash" and
then study the driver a bit to see if indeed it seems like that the
firmware crashes there. In *many* cases there is even infrastructure
for this, so this is sometimes clearly obvious. Some other times it
required a bit of deciphering.

The diff stat below is what I have so far, however the patch below
only includes the drivers that start with Q, as they were a source of
inspiration for this, and to make this RFC easier to read.

If this seems sensible, I can follow up with the kernel helper first,
and then tackle each subsystem independently.

I purposely skipped review of remoteproc and virtualization. That should
require its own separate careful review and considerations.

 drivers/atm/nicstar.c                               |  1 +
 drivers/bluetooth/hci_qca.c                         |  1 +
 drivers/gpu/drm/i915/i915_gpu_error.c               |  1 +
 drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c         |  2 ++
 drivers/gpu/drm/msm/msm_gpu.c                       |  1 +
 drivers/media/dvb-frontends/sp8870.c                |  1 +
 drivers/media/pci/ttpci/av7110.c                    |  1 +
 drivers/misc/mic/cosm/cosm_scif_server.c            |  1 +
 drivers/net/ethernet/8390/axnet_cs.c                |  4 +++-
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c    |  1 +
 drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c   |  1 +
 drivers/net/ethernet/brocade/bna/bfa_ioc.c          |  1 +
 drivers/net/ethernet/cavium/liquidio/lio_main.c     |  1 +
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c     |  1 +
 drivers/net/ethernet/ibm/ehea/ehea_main.c           |  2 ++
 drivers/net/ethernet/qlogic/qed/qed_debug.c         |  3 +++
 drivers/net/ipa/ipa_modem.c                         |  1 +
 drivers/net/wimax/i2400m/rx.c                       |  1 +
 drivers/net/wireless/ath/ath10k/pci.c               |  2 ++
 drivers/net/wireless/ath/ath10k/sdio.c              |  2 ++
 drivers/net/wireless/ath/ath10k/snoc.c              |  1 +
 drivers/net/wireless/ath/ath6kl/hif.c               |  1 +
 .../net/wireless/broadcom/brcm80211/brcmfmac/core.c |  1 +
 drivers/net/wireless/marvell/mwl8k.c                |  1 +
 drivers/scsi/bfa/bfa_ioc.c                          |  1 +
 drivers/scsi/megaraid/megaraid_sas_fusion.c         |  1 +
 drivers/scsi/qla4xxx/ql4_mbx.c                      |  2 ++
 drivers/staging/media/omap4iss/iss.c                |  1 +
 include/linux/kernel.h                              |  3 ++-
 include/linux/module.h                              | 13 +++++++++++++
 include/trace/events/module.h                       |  3 ++-
 kernel/module.c                                     |  5 +++--
 kernel/panic.c                                      |  1 +
 33 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_debug.c b/drivers/net/ethernet/qlogic/qed/qed_debug.c
index f4eebaabb6d0..9cc6287b889b 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_debug.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_debug.c
@@ -7854,6 +7854,7 @@ int qed_dbg_all_data(struct qed_dev *cdev, void *buffer)
 						 REGDUMP_HEADER_SIZE,
 						 &feature_size);
 		if (!rc) {
+			module_firmware_crashed();
 			*(u32 *)((u8 *)buffer + offset) =
 			    qed_calc_regdump_header(cdev, PROTECTION_OVERRIDE,
 						    cur_engine,
@@ -7869,6 +7870,7 @@ int qed_dbg_all_data(struct qed_dev *cdev, void *buffer)
 		rc = qed_dbg_fw_asserts(cdev, (u8 *)buffer + offset +
 					REGDUMP_HEADER_SIZE, &feature_size);
 		if (!rc) {
+			module_firmware_crashed();
 			*(u32 *)((u8 *)buffer + offset) =
 			    qed_calc_regdump_header(cdev, FW_ASSERTS,
 						    cur_engine, feature_size,
@@ -7906,6 +7908,7 @@ int qed_dbg_all_data(struct qed_dev *cdev, void *buffer)
 		rc = qed_dbg_grc(cdev, (u8 *)buffer + offset +
 				 REGDUMP_HEADER_SIZE, &feature_size);
 		if (!rc) {
+			module_firmware_crashed();
 			*(u32 *)((u8 *)buffer + offset) =
 			    qed_calc_regdump_header(cdev, GRC_DUMP,
 						    cur_engine,
diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index 1d941d53fdc9..6bd0f3b518b9 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -1767,6 +1767,7 @@ static void ath10k_pci_fw_dump_work(struct work_struct *work)
 		scnprintf(guid, sizeof(guid), "n/a");
 
 	ath10k_err(ar, "firmware crashed! (guid %s)\n", guid);
+	module_firmware_crashed();
 	ath10k_print_driver_info(ar);
 	ath10k_pci_dump_registers(ar, crash_data);
 	ath10k_ce_dump_registers(ar, crash_data);
@@ -2837,6 +2838,7 @@ static int ath10k_pci_hif_power_up(struct ath10k *ar,
 	if (ret) {
 		if (ath10k_pci_has_fw_crashed(ar)) {
 			ath10k_warn(ar, "firmware crashed during chip reset\n");
+			module_firmware_crashed();
 			ath10k_pci_fw_crashed_clear(ar);
 			ath10k_pci_fw_crashed_dump(ar);
 		}
diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c
index e2aff2254a40..d34ad289380f 100644
--- a/drivers/net/wireless/ath/ath10k/sdio.c
+++ b/drivers/net/wireless/ath/ath10k/sdio.c
@@ -794,6 +794,7 @@ static int ath10k_sdio_mbox_proc_dbg_intr(struct ath10k *ar)
 
 	/* TODO: Add firmware crash handling */
 	ath10k_warn(ar, "firmware crashed\n");
+	module_firmware_crashed();
 
 	/* read counter to clear the interrupt, the debug error interrupt is
 	 * counter 0.
@@ -915,6 +916,7 @@ static int ath10k_sdio_mbox_proc_cpu_intr(struct ath10k *ar)
 	if (cpu_int_status & MBOX_CPU_STATUS_ENABLE_ASSERT_MASK) {
 		ath10k_err(ar, "firmware crashed!\n");
 		queue_work(ar->workqueue, &ar->restart_work);
+		module_firmware_crashed();
 	}
 	return ret;
 }
diff --git a/drivers/net/wireless/ath/ath10k/snoc.c b/drivers/net/wireless/ath/ath10k/snoc.c
index 354d49b1cd45..7cfc123c345c 100644
--- a/drivers/net/wireless/ath/ath10k/snoc.c
+++ b/drivers/net/wireless/ath/ath10k/snoc.c
@@ -1451,6 +1451,7 @@ void ath10k_snoc_fw_crashed_dump(struct ath10k *ar)
 		scnprintf(guid, sizeof(guid), "n/a");
 
 	ath10k_err(ar, "firmware crashed! (guid %s)\n", guid);
+	module_firmware_crashed();
 	ath10k_print_driver_info(ar);
 	ath10k_msa_dump_memory(ar, crash_data);
 	mutex_unlock(&ar->dump_mutex);
diff --git a/drivers/net/wireless/ath/ath6kl/hif.c b/drivers/net/wireless/ath/ath6kl/hif.c
index d1942537ea10..cfd838607544 100644
--- a/drivers/net/wireless/ath/ath6kl/hif.c
+++ b/drivers/net/wireless/ath/ath6kl/hif.c
@@ -120,6 +120,7 @@ static int ath6kl_hif_proc_dbg_intr(struct ath6kl_device *dev)
 	int ret;
 
 	ath6kl_warn("firmware crashed\n");
+	module_firmware_crashed();
 
 	/*
 	 * read counter to clear the interrupt, the debug error interrupt is
diff --git a/drivers/scsi/qla4xxx/ql4_mbx.c b/drivers/scsi/qla4xxx/ql4_mbx.c
index 02636b4785c5..39a58ba5df0a 100644
--- a/drivers/scsi/qla4xxx/ql4_mbx.c
+++ b/drivers/scsi/qla4xxx/ql4_mbx.c
@@ -1016,6 +1016,8 @@ void qla4xxx_get_crash_record(struct scsi_qla_host * ha)
 	dma_addr_t crash_record_dma = 0;
 	uint32_t crash_record_size = 0;
 
+	module_firmware_crashed();
+
 	memset(&mbox_cmd, 0, sizeof(mbox_cmd));
 	memset(&mbox_sts, 0, sizeof(mbox_cmd));
 
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 04a5885cec1b..19e1541c82c7 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -601,7 +601,8 @@ extern enum system_states {
 #define TAINT_LIVEPATCH			15
 #define TAINT_AUX			16
 #define TAINT_RANDSTRUCT		17
-#define TAINT_FLAGS_COUNT		18
+#define TAINT_FIRMWARE_CRASH		18
+#define TAINT_FLAGS_COUNT		19
 
 struct taint_flag {
 	char c_true;	/* character printed when tainted */
diff --git a/include/linux/module.h b/include/linux/module.h
index 1ad393e62bef..de9156dfe6bb 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -697,6 +697,14 @@ static inline bool is_livepatch_module(struct module *mod)
 bool is_module_sig_enforced(void);
 void set_module_sig_enforced(void);
 
+void add_taint_module(struct module *mod, unsigned flag,
+		      enum lockdep_ok lockdep_ok);
+
+static inline void module_firmware_crashed(void)
+{
+	add_taint_module(THIS_MODULE, TAINT_FIRMWARE_CRASH, LOCKDEP_STILL_OK);
+}
+
 #else /* !CONFIG_MODULES... */
 
 static inline struct module *__module_address(unsigned long addr)
@@ -844,6 +852,11 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr)
 	return ptr;
 }
 
+static inline void module_firmware_crashed(void)
+{
+	add_taint(TAINT_FIRMWARE_CRASH, val);
+}
+
 #endif /* CONFIG_MODULES */
 
 #ifdef CONFIG_SYSFS
diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 097485c73c01..b749ea25affd 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -26,7 +26,8 @@ struct module;
 	{ (1UL << TAINT_OOT_MODULE),		"O" },		\
 	{ (1UL << TAINT_FORCED_MODULE),		"F" },		\
 	{ (1UL << TAINT_CRAP),			"C" },		\
-	{ (1UL << TAINT_UNSIGNED_MODULE),	"E" })
+	{ (1UL << TAINT_UNSIGNED_MODULE),	"E" },		\
+	{ (1UL << TAINT_FIRMWARE_CRASH),	"Q" })
 
 TRACE_EVENT(module_load,
 
diff --git a/kernel/module.c b/kernel/module.c
index d626dc31b37f..06e6e645dbd4 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -325,12 +325,13 @@ static inline int strong_try_module_get(struct module *mod)
 		return -ENOENT;
 }
 
-static inline void add_taint_module(struct module *mod, unsigned flag,
-				    enum lockdep_ok lockdep_ok)
+void add_taint_module(struct module *mod, unsigned flag,
+		      enum lockdep_ok lockdep_ok)
 {
 	add_taint(flag, lockdep_ok);
 	set_bit(flag, &mod->taints);
 }
+EXPORT_SYMBOL_GPL(add_taint_module);
 
 /*
  * A thread that wants to hold a reference to a module only while it
diff --git a/kernel/panic.c b/kernel/panic.c
index ec6d7d788ce7..504fb926947e 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -384,6 +384,7 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
 	[ TAINT_LIVEPATCH ]		= { 'K', ' ', true },
 	[ TAINT_AUX ]			= { 'X', ' ', true },
 	[ TAINT_RANDSTRUCT ]		= { 'T', ' ', true },
+	[ TAINT_FIRMWARE_CRASH ]	= { 'Q', ' ', true },
 };
 
 /**
-- 
2.25.1