tpm: Replace WARN_ONCE() with dev_err_once() in tpm_tis_status()
Subsystems (3)
Jarkko Sakkinen
maintainerPATCH v2 1/1 tpm: Replace WARN_ONCE() with dev_err_once() in tpm_tis_status()
Do not torn down the system when getting invalid status from a TPM chip. This can happen when panic-on-warn is used.
In addition, print out the value of TPM_STS.x instead of "invalid status". In order to get the earlier benefits for forensics, also call dump_stack().
---
v2:
Dump also stack only once.
drivers/char/tpm/tpm_tis_core.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-)
drivers/char/tpm/tpm_tis_core.c +20 -8
@@ -188,21 +188,33 @@ static int request_locality(struct tpm_chip *chip, int l)static u8 tpm_tis_status (struct tpm_chip *chip) {struct tpm_tis_data *priv =dev_get_drvdata (&chip->dev); -int rc; +static unsigned long klog_once;u8 status; +int rc; rc =tpm_tis_read8 (priv,TPM_STS (priv->locality), &status);if (rc <0 )return 0 ;if (unlikely ((status &TPM_STS_READ_ZERO ) !=0 )) { -/* -* If this trips, the chances are the read is -* returning 0xff because the locality hasn't been -* acquired. Usually because tpm_try_get_ops() hasn't -* been called before doing a TPM operation. -*/ -WARN_ONCE (1 ,"TPM returned invalid status\n" ); +if (!test_and_set_bit (BIT (0 ), &klog_once)) { +/* +* If this trips, the chances are the read is +* returning 0xff because the locality hasn't been +* acquired. Usually because tpm_try_get_ops() hasn't +* been called before doing a TPM operation. +*/ +dev_err (&chip->dev,"invalid TPM_STS.x 0x%02x, dumping stack for forensics\n" , + status); + +/* +* Dump stack for forensics, as invalid TPM_STS.x could be +* potentially triggered by impaired tpm_try_get_ops() or +* tpm_find_get_ops(). +*/ +dump_stack (); + } +return 0 ; }
Signature · 1 line
2.31.1
Quoted 13 lines · Jarkko Sakkinen
Do not torn down the system when getting invalid status from a TPM chip. This can happen when panic-on-warn is used.
In addition, print out the value of TPM_STS.x instead of "invalid status". In order to get the earlier benefits for forensics, also call
dump_stack().Fixes 55707d531af6 ("tpm_tis: Add a check for invalid status")Cc Hans de Goede <[email protected]>Cc Greg KH <[email protected]>Signed-off-by Jarkko Sakkinen <[email protected]>
Quoted 4 lines
---
v2:
Dump also stack only once.
Huh?
Quoted 20 lines
drivers/char/tpm/tpm_tis_core.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-)drivers/char/tpm/tpm_tis_core.c +2
-1@@ -188,21 +188,33 @@ static int request_locality(struct tpm_chip *chip, int l)static u8 tpm_tis_status (struct tpm_chip *chip) {struct tpm_tis_data *priv =dev_get_drvdata (&chip->dev); -int rc; +static unsigned long klog_once;u8 status; +int rc; rc =tpm_tis_read8 (priv,TPM_STS (priv->locality), &status);if (rc <0 )return 0 ;
drivers/char/tpm/tpm_tis_core.c static int request_locality(struct tpm_chip *chip, int l) · line 200
Quoted 10 lines
drivers/char/tpm/tpm_tis_core.c +1
-7if (unlikely ((status &TPM_STS_READ_ZERO ) !=0 )) { -/* -* If this trips, the chances are the read is -* returning 0xff because the locality hasn't been -* acquired. Usually because tpm_try_get_ops() hasn't -* been called before doing a TPM operation. -*/ -WARN_ONCE (1 ,"TPM returned invalid status\n" ); +if (!test_and_set_bit (BIT (0 ), &klog_once)) {
Odd whitespace...
Anyway, why? Isn't this what the ratelimit stuff should give you? How badly is this being tripped so much so that you need to only do this once per entire system and not per-device?
thanks,
greg k-h
Jarkko Sakkinen
maintainerQuoted 54 lines · Greg KH
Quoted 13 lines · Jarkko Sakkinen
Do not torn down the system when getting invalid status from a TPM chip. This can happen when panic-on-warn is used.
In addition, print out the value of TPM_STS.x instead of "invalid status". In order to get the earlier benefits for forensics, also call
dump_stack().Fixes 55707d531af6 ("tpm_tis: Add a check for invalid status")Cc Hans de Goede <[email protected]>Cc Greg KH <[email protected]>Signed-off-by Jarkko Sakkinen <[email protected]>Quoted 4 lines
---
v2:
Dump also stack only once.Huh?
Quoted 20 lines
drivers/char/tpm/tpm_tis_core.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-)drivers/char/tpm/tpm_tis_core.c +2
-1@@ -188,21 +188,33 @@ static int request_locality(struct tpm_chip *chip, int l)static u8 tpm_tis_status (struct tpm_chip *chip) {struct tpm_tis_data *priv =dev_get_drvdata (&chip->dev); -int rc; +static unsigned long klog_once;u8 status; +int rc; rc =tpm_tis_read8 (priv,TPM_STS (priv->locality), &status);if (rc <0 )return 0 ;drivers/char/tpm/tpm_tis_core.c static int request_locality(struct tpm_chip *chip, int l) · line 200
Quoted 10 lines
drivers/char/tpm/tpm_tis_core.c +1
-7if (unlikely ((status &TPM_STS_READ_ZERO ) !=0 )) { -/* -* If this trips, the chances are the read is -* returning 0xff because the locality hasn't been -* acquired. Usually because tpm_try_get_ops() hasn't -* been called before doing a TPM operation. -*/ -WARN_ONCE (1 ,"TPM returned invalid status\n" ); +if (!test_and_set_bit (BIT (0 ), &klog_once)) {Odd whitespace...
Quoted 3 lines
Anyway, why? Isn't this what the ratelimit stuff should give you? How badly is this being tripped so much so that you need to only do this once per entire system and not per-device?
The problem with "v1" was that the message was printed once, but the dump_stack() was called however many times. And ratelimited stuff is afaik only for printk's, there's no ratelimited dump_stack().
What you're saying makes sense tho. It would be sane behaviour to do this once-per-device, instead of just once.
Since struct tpm_chip already has a bitmask flags, I'll just add a TPM_CHIP_FLAG_INVALID_STATUS, and:
if (test_and_set_bit(TPM_CHIP_FLAG_INVALID_STATUS, &chip->flags)) {
/* ... */Quoted 3 lines
thanks,
greg k-h
Thank you.
/Jarkko