Hi, On 11.07.23 02:50, Jarkko Sakkinen wrote: > > BTW, you should do next time: > > git format-patch -v4 to get "[PATCH v4]", which defacto way to mark up > patch set versions. > Right, will do so the next time. > 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. Ok. > >> +{ >> + 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: */ Hmm ok. I thought a little description about why devm_free_irq() has to be deferred would be helpful. But maybe it is obvious and one sentence is enough. > >> + 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? > This function is supposed to check if an interrupt storm has occured. So tpm_tis_check_for_interrupt_storm seems to be proper name. >> +{ >> + 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"). Right, there are some words missing. I think this should be something like "...the worker that is supposed 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. > Ok, what about "In case of success return IRQ_HANDLED to prevent the genirq code from starting its own interrupt storm handling". >> + 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 ok > >> >> 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; >> Regards, Lino
