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From:   adam radford <aradford@gmail.com>
Date:   Fri, 10 Nov 2017 11:42:06 -0800
Message-ID: <CAHtARFH+2T6J05GySxoMNzSN21WCm1S0XgD7K0UE8Nr5sBjeFw@mail.gmail.com>
Subject: Re: [PATCH 1/3] scsi: 3ware: fix 32-bit time calculations
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sumit Saxena <sumit.saxena@broadcom.com>,
        linux-scsi <linux-scsi@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Fri, Nov 10, 2017 at 7:58 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> twl_aen_queue_event/twa_aen_queue_event, we use do_gettimeofday()
> to read the lower 32 bits of the current time in seconds, to pass
> them to the TW_IOCTL_GET_NEXT_EVENT ioctl or the 3ware_aen_read
> sysfs file.
>
> This will overflow on all architectures in year 2106, there is
> not much we can do about that without breaking the ABI. User
> space has 90 years to learn to deal with it, so it's probably ok.
>
> I'm changing it to use ktime_get_real_seconds() with a comment
> to document what happens when.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/scsi/3w-9xxx.c | 5 ++---
>  drivers/scsi/3w-sas.c  | 5 ++---
>  2 files changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c
> index 00e7968a1d70..cb9af3f7b653 100644
> --- a/drivers/scsi/3w-9xxx.c
> +++ b/drivers/scsi/3w-9xxx.c
> @@ -369,7 +369,6 @@ static int twa_aen_drain_queue(TW_Device_Extension *tw_dev, int no_check_reset)
>  static void twa_aen_queue_event(TW_Device_Extension *tw_dev, TW_Command_Apache_Header *header)
>  {
>         u32 local_time;
> -       struct timeval time;
>         TW_Event *event;
>         unsigned short aen;
>         char host[16];
> @@ -392,8 +391,8 @@ static void twa_aen_queue_event(TW_Device_Extension *tw_dev, TW_Command_Apache_H
>         memset(event, 0, sizeof(TW_Event));
>
>         event->severity = TW_SEV_OUT(header->status_block.severity__reserved);
> -       do_gettimeofday(&time);
> -       local_time = (u32)(time.tv_sec - (sys_tz.tz_minuteswest * 60));
> +       /* event->time_stamp_sec overflows in y2106 */
> +       local_time = (u32)(ktime_get_real_seconds() - (sys_tz.tz_minuteswest * 60));
>         event->time_stamp_sec = local_time;
>         event->aen_code = aen;
>         event->retrieved = TW_AEN_NOT_RETRIEVED;
> diff --git a/drivers/scsi/3w-sas.c b/drivers/scsi/3w-sas.c
> index b150e131b2e7..c283fdb3cb24 100644
> --- a/drivers/scsi/3w-sas.c
> +++ b/drivers/scsi/3w-sas.c
> @@ -221,7 +221,6 @@ static char *twl_aen_severity_lookup(unsigned char severity_code)
>  static void twl_aen_queue_event(TW_Device_Extension *tw_dev, TW_Command_Apache_Header *header)
>  {
>         u32 local_time;
> -       struct timeval time;
>         TW_Event *event;
>         unsigned short aen;
>         char host[16];
> @@ -240,8 +239,8 @@ static void twl_aen_queue_event(TW_Device_Extension *tw_dev, TW_Command_Apache_H
>         memset(event, 0, sizeof(TW_Event));
>
>         event->severity = TW_SEV_OUT(header->status_block.severity__reserved);
> -       do_gettimeofday(&time);
> -       local_time = (u32)(time.tv_sec - (sys_tz.tz_minuteswest * 60));
> +       /* event->time_stamp_sec overflows in y2106 */
> +       local_time = (u32)(ktime_get_real_seconds() - (sys_tz.tz_minuteswest * 60));
>         event->time_stamp_sec = local_time;
>         event->aen_code = aen;
>         event->retrieved = TW_AEN_NOT_RETRIEVED;
> --
> 2.9.0
>

Acked-by: Adam Radford <aradford@gmail.com>

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