From 655603de68469adaff16842ac17a5aec9c9ce89b Mon Sep 17 00:00:00 2001 From: Duncan Laurie Date: Fri, 12 Oct 2018 10:04:45 -0600 Subject: [PATCH] gsmi: Fix bug in append_to_eventlog sysfs handler The sysfs handler should return the number of bytes consumed, which in the case of a successful write is the entire buffer. Also fix a bug where param.data_len was being set to (count - (2 * sizeof(u32))) instead of just (count - sizeof(u32)). The latter is correct because we skip over the leading u32 which is our param.type, but we were also incorrectly subtracting sizeof(u32) on the line where we were actually setting param.data_len: param.data_len = count - sizeof(u32); This meant that for our example event.kernel_software_watchdog with total length 10 bytes, param.data_len was just 2 prior to this change. To test, successfully append an event to the log with gsmi sysfs. This sample event is for a "Kernel Software Watchdog" > xxd -g 1 event.kernel_software_watchdog 0000000: 01 00 00 00 ad de 06 00 00 00 > cat event.kernel_software_watchdog > /sys/firmware/gsmi/append_to_eventlog > mosys eventlog list | tail -1 14 | 2012-06-25 10:14:14 | Kernl Event | Software Watchdog Signed-off-by: Duncan Laurie Reviewed-by: Vadim Bendebury Reviewed-by: Stefan Reinauer Signed-off-by: Furquan Shaikh Tested-by: Furquan Shaikh Reviewed-by: Aaron Durbin Reviewed-by: Justin TerAvest [zwisler: updated changelog for 2nd bug fix and upstream] Signed-off-by: Ross Zwisler Reviewed-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/google/gsmi.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c index 734146eec1b9..3677d511f4c4 100644 --- a/drivers/firmware/google/gsmi.c +++ b/drivers/firmware/google/gsmi.c @@ -480,11 +480,10 @@ static ssize_t eventlog_write(struct file *filp, struct kobject *kobj, if (count < sizeof(u32)) return -EINVAL; param.type = *(u32 *)buf; - count -= sizeof(u32); buf += sizeof(u32); /* The remaining buffer is the data payload */ - if (count > gsmi_dev.data_buf->length) + if ((count - sizeof(u32)) > gsmi_dev.data_buf->length) return -EINVAL; param.data_len = count - sizeof(u32); @@ -504,7 +503,7 @@ static ssize_t eventlog_write(struct file *filp, struct kobject *kobj, spin_unlock_irqrestore(&gsmi_dev.lock, flags); - return rc; + return (rc == 0) ? count : rc; }