BTW, you should do next time: git format-patch -v4 to get "[PATCH v4]", which defacto way to mark up patch set versions. On Mon Jun 19, 2023 at 12:22 PM EEST, Lino Sanfilippo wrote: > From: Lino Sanfilippo <l.sanfilippo@xxxxxxxxxx> > > After activation of interrupts for TPM TIS drivers 0-day reports an > interrupt storm on an Inspur NF5180M6 server. > > Fix this by detecting the storm and falling back to polling: > Count the number of unhandled interrupts within a 10 ms time interval. In > case that more than 1000 were unhandled deactivate interrupts entirely, > deregister the handler and use polling instead. > > Also print a note to point to the tpm_tis_dmi_table. > > Since the interrupt deregistration function devm_free_irq() waits for all > interrupt handlers to finish, only trigger a worker in the interrupt > handler and do the unregistration in the worker to avoid a deadlock. > > Note: the storm detection logic equals the implementation in > note_interrupt() which uses timestamps and counters stored in struct > irq_desc. Since this structure is private to the generic interrupt core > the TPM TIS core uses its own timestamps and counters. Furthermore the TPM > interrupt handler always returns IRQ_HANDLED to prevent the generic > interrupt core from processing the interrupt storm. > > Reported-by: kernel test robot <yujie.liu@xxxxxxxxx> > Closes: https://lore.kernel.org/oe-lkp/202305041325.ae8b0c43-yujie.liu@xxxxxxxxx/ > Suggested-by: Lukas Wunner <lukas@xxxxxxxxx> > Signed-off-by: Lino Sanfilippo <l.sanfilippo@xxxxxxxxxx> > --- > drivers/char/tpm/tpm_tis_core.c | 117 ++++++++++++++++++++++++++++---- > drivers/char/tpm/tpm_tis_core.h | 4 ++ > 2 files changed, 106 insertions(+), 15 deletions(-) > > Changes to v2: > - use define for max number of unhandles irqs(requested by Jarko) > - rename intmask to int_mask (requested by Jarko) > - rephrased short summary (requested by Jarko) > - rename disable_interrupts to tpm_tis_disable_interrupts (requested by Jarko) > - print info message concerning adding an entry to tpm_tis_dmi_table > (suggested by Jerry) > - amended commit message > - handle failure of locality request by returning IRQ_NONE > - dont take and release locality in __tpm_tis_disable_interrupts but in its > caller > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index 558144fa707a..d42537b985c5 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -24,9 +24,12 @@ > #include <linux/wait.h> > #include <linux/acpi.h> > #include <linux/freezer.h> > +#include <linux/dmi.h> > #include "tpm.h" > #include "tpm_tis_core.h" > > +#define TPM_TIS_MAX_UNHANDLED_IRQS 1000 > + > static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value); > > static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask, > @@ -468,25 +471,29 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) > return rc; > } > > -static void disable_interrupts(struct tpm_chip *chip) > +static void __tpm_tis_disable_interrupts(struct tpm_chip *chip) > +{ > + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > + u32 int_mask = 0; > + > + tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &int_mask); > + int_mask &= ~TPM_GLOBAL_INT_ENABLE; > + tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), int_mask); > + > + chip->flags &= ~TPM_CHIP_FLAG_IRQ; > +} > + > +static void tpm_tis_disable_interrupts(struct tpm_chip *chip) > { > struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > - u32 intmask; > - int rc; > > if (priv->irq == 0) > return; > > - rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask); > - if (rc < 0) > - intmask = 0; > - > - intmask &= ~TPM_GLOBAL_INT_ENABLE; > - rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask); > + __tpm_tis_disable_interrupts(chip); > > devm_free_irq(chip->dev.parent, priv->irq, chip); > priv->irq = 0; > - chip->flags &= ~TPM_CHIP_FLAG_IRQ; > } These look pretty good. > > /* > @@ -552,7 +559,7 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len) > if (!test_bit(TPM_TIS_IRQ_TESTED, &priv->flags)) > tpm_msleep(1); > if (!test_bit(TPM_TIS_IRQ_TESTED, &priv->flags)) > - disable_interrupts(chip); > + tpm_tis_disable_interrupts(chip); > set_bit(TPM_TIS_IRQ_TESTED, &priv->flags); > return rc; > } > @@ -752,6 +759,71 @@ static bool tpm_tis_req_canceled(struct tpm_chip *chip, u8 status) > return status == TPM_STS_COMMAND_READY; > } > > +static irqreturn_t tpm_tis_reenable_polling(struct tpm_chip *chip) I'd rename this to tpm_tis_revert_interrupts(), as it reverts enabling the interrupts. Polling was never enabled in a fully initialized driver so the function name is implying something that never happened. > +{ > + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > + const char *product; > + const char *vendor; > + > + dev_warn(&chip->dev, FW_BUG > + "TPM interrupt storm detected, polling instead\n"); > + > + vendor = dmi_get_system_info(DMI_SYS_VENDOR); > + product = dmi_get_system_info(DMI_PRODUCT_VERSION); > + > + if (vendor && product) { > + dev_info(&chip->dev, > + "Consider adding the following entry to tpm_tis_dmi_table:\n"); > + dev_info(&chip->dev, "\tDMI_SYS_VENDOR: %s\n", vendor); > + dev_info(&chip->dev, "\tDMI_PRODUCT_VERSION: %s\n", product); > + } > + > + if (tpm_tis_request_locality(chip, 0) != 0) > + return IRQ_NONE; > + > + __tpm_tis_disable_interrupts(chip); > + tpm_tis_relinquish_locality(chip, 0); > + > + /* > + * devm_free_irq() must not be called from within the interrupt handler, > + * since this function waits for running handlers to finish and thus it > + * would deadlock. Instead trigger a worker that takes care of the > + * unregistration. > + */ Way too complex description. This should do: /* Defer devm_free_irq() outside the interrupt context: */ > + schedule_work(&priv->free_irq_work); > + > + return IRQ_HANDLED; > +} > + > +static irqreturn_t tpm_tis_check_for_interrupt_storm(struct tpm_chip *chip) What does checking interrupt storm mean, anyway? > +{ > + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > + irqreturn_t irqret = IRQ_HANDLED; > + > + /* > + * The worker to free the TPM interrupt (free_irq_work) may already > + * be scheduled, so make sure it is not scheduled again. > + */ I don't understand the text in the comment. It is not even a proper sentence ("to work to free"). > + if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) > + return IRQ_HANDLED; > + > + if (time_after(jiffies, priv->last_unhandled_irq + HZ/10)) > + priv->unhandled_irqs = 1; > + else > + priv->unhandled_irqs++; > + > + priv->last_unhandled_irq = jiffies; > + > + if (priv->unhandled_irqs > TPM_TIS_MAX_UNHANDLED_IRQS) > + irqret = tpm_tis_reenable_polling(chip); > + > + /* > + * Prevent the genirq code from starting its own interrupt storm > + * handling by always reporting that the interrupt was handled. > + */ Ditto, textual content is confusing. You can either make them more informative, or add a short description before the function. > + return irqret; > +} > + > static irqreturn_t tis_int_handler(int dummy, void *dev_id) > { > struct tpm_chip *chip = dev_id; > @@ -761,10 +833,10 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id) > > rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt); > if (rc < 0) > - return IRQ_NONE; > + goto unhandled; s/unhandled/err/g > > if (interrupt == 0) > - return IRQ_NONE; > + goto unhandled; > > set_bit(TPM_TIS_IRQ_TESTED, &priv->flags); > if (interrupt & TPM_INTF_DATA_AVAIL_INT) > @@ -780,10 +852,13 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id) > rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), interrupt); > tpm_tis_relinquish_locality(chip, 0); > if (rc < 0) > - return IRQ_NONE; > + goto unhandled; > > tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt); > return IRQ_HANDLED; > + > +unhandled: > + return tpm_tis_check_for_interrupt_storm(chip); > } > > static void tpm_tis_gen_interrupt(struct tpm_chip *chip) > @@ -804,6 +879,15 @@ static void tpm_tis_gen_interrupt(struct tpm_chip *chip) > chip->flags &= ~TPM_CHIP_FLAG_IRQ; > } > > +static void tpm_tis_free_irq_func(struct work_struct *work) > +{ > + struct tpm_tis_data *priv = container_of(work, typeof(*priv), free_irq_work); > + struct tpm_chip *chip = priv->chip; > + > + devm_free_irq(chip->dev.parent, priv->irq, chip); > + priv->irq = 0; > +} > + > /* Register the IRQ and issue a command that will cause an interrupt. If an > * irq is seen then leave the chip setup for IRQ operation, otherwise reverse > * everything and leave in polling mode. Returns 0 on success. > @@ -816,6 +900,7 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask, > int rc; > u32 int_status; > > + INIT_WORK(&priv->free_irq_work, tpm_tis_free_irq_func); > > rc = devm_request_threaded_irq(chip->dev.parent, irq, NULL, > tis_int_handler, IRQF_ONESHOT | flags, > @@ -918,6 +1003,7 @@ void tpm_tis_remove(struct tpm_chip *chip) > interrupt = 0; > > tpm_tis_write32(priv, reg, ~TPM_GLOBAL_INT_ENABLE & interrupt); > + flush_work(&priv->free_irq_work); > > tpm_tis_clkrun_enable(chip, false); > > @@ -1021,6 +1107,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > chip->timeout_b = msecs_to_jiffies(TIS_TIMEOUT_B_MAX); > chip->timeout_c = msecs_to_jiffies(TIS_TIMEOUT_C_MAX); > chip->timeout_d = msecs_to_jiffies(TIS_TIMEOUT_D_MAX); > + priv->chip = chip; > priv->timeout_min = TPM_TIMEOUT_USECS_MIN; > priv->timeout_max = TPM_TIMEOUT_USECS_MAX; > priv->phy_ops = phy_ops; > @@ -1179,7 +1266,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > rc = tpm_tis_request_locality(chip, 0); > if (rc < 0) > goto out_err; > - disable_interrupts(chip); > + tpm_tis_disable_interrupts(chip); > tpm_tis_relinquish_locality(chip, 0); > } > } > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > index 610bfadb6acf..b1a169d7d1ca 100644 > --- a/drivers/char/tpm/tpm_tis_core.h > +++ b/drivers/char/tpm/tpm_tis_core.h > @@ -91,11 +91,15 @@ enum tpm_tis_flags { > }; > > struct tpm_tis_data { > + struct tpm_chip *chip; > u16 manufacturer_id; > struct mutex locality_count_mutex; > unsigned int locality_count; > int locality; > int irq; > + struct work_struct free_irq_work; > + unsigned long last_unhandled_irq; > + unsigned int unhandled_irqs; > unsigned int int_mask; > unsigned long flags; > void __iomem *ilb_base_addr; > > base-commit: 45a3e24f65e90a047bef86f927ebdc4c710edaa1 > -- > 2.40.1 BR, Jarkko
