On 05.10.20 12:21, Heinrich Schuchardt wrote:
> When a message is written by a log driver (e.g. via the network stack) this
> may result in the generation of further messages. We cannot allow these
> additional messages to be emitted as this might result in an infinite
> recursion.
>
> Up to now only the syslog driver was safeguarded. We should safeguard all
> log drivers instead.
>
> Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de>
> ---
> This patch is based on
>
> [PATCH v3 0/3] doc: global data pointer
> https://lists.denx.de/pipermail/u-boot/2020-October/428475.html
>
> v2:
> move processing_msg to global data pointer
> (Simon reported a problem with SPL log messages when useing a
> static variable)
Hello Simon,
this is what is needed based on origin/master.
In origin/next the first version of the patch was merged.
What should I use as basis?
Best regards
Heinrich
> ---
> common/log.c | 12 +++++++++++-
> common/log_syslog.c | 8 --------
> include/asm-generic/global_data.h | 8 ++++++++
> 3 files changed, 19 insertions(+), 9 deletions(-)
>
> diff --git a/common/log.c b/common/log.c
> index 734d26de4a..54f2fdeb36 100644
> --- a/common/log.c
> +++ b/common/log.c
> @@ -192,11 +192,21 @@ static int log_dispatch(struct log_rec *rec)
> {
> struct log_device *ldev;
>
> + /*
> + * When a log driver writes messages (e.g. via the network stack) this
> + * may result in further generated messages. We cannot process them here
> + * as this might result in infinite recursion.
> + */
> + if (gd->processing_msg)
> + return 0;
> +
> + /* Emit message */
> + gd->processing_msg = 1;
> list_for_each_entry(ldev, &gd->log_head, sibling_node) {
> if (log_passes_filters(ldev, rec))
> ldev->drv->emit(ldev, rec);
> }
> -
> + gd->processing_msg = 0;
> return 0;
> }
>
> diff --git a/common/log_syslog.c b/common/log_syslog.c
> index 149ff5af31..2ae703fed7 100644
> --- a/common/log_syslog.c
> +++ b/common/log_syslog.c
> @@ -35,16 +35,9 @@ static int log_syslog_emit(struct log_device *ldev, struct
> log_rec *rec)
> char *log_msg;
> int eth_hdr_size;
> struct in_addr bcast_ip;
> - static int processing_msg;
> unsigned int log_level;
> char *log_hostname;
>
> - /* Fend off messages from the network stack while writing a message */
> - if (processing_msg)
> - return 0;
> -
> - processing_msg = 1;
> -
> /* Setup packet buffers */
> net_init();
> /* Disable hardware and put it into the reset state */
> @@ -108,7 +101,6 @@ static int log_syslog_emit(struct log_device *ldev,
> struct log_rec *rec)
> net_send_packet((uchar *)msg, ptr - msg);
>
> out:
> - processing_msg = 0;
> return ret;
> }
>
> diff --git a/include/asm-generic/global_data.h
> b/include/asm-generic/global_data.h
> index ebb740d34f..6bb7f93678 100644
> --- a/include/asm-generic/global_data.h
> +++ b/include/asm-generic/global_data.h
> @@ -363,6 +363,14 @@ struct global_data {
> * &enum log_fmt defines the bits of the bit mask.
> */
> int log_fmt;
> +
> + /**
> + * @processing_msg: a log message is being processed
> + *
> + * This flag is used to suppress the creation of additional messages
> + * while another message is being processed.
> + */
> + int processing_msg;
> #endif
> #if CONFIG_IS_ENABLED(BLOBLIST)
> /**
> --
> 2.28.0
>
