| Message ID | 20200103004638.16307-3-ynezz@true.cz |
|---|---|
| State | Accepted |
| Delegated to: | Petr Štetiar |
| Headers | show |
| Series | fixes and improvements | expand |
On 1/3/20 1:46 AM, Petr Štetiar wrote: > It was quite common to see following error during sysupgrade on serial > console: > > Failed to parse JSON: 4 > > This is happening due to the fact, that validate_firmware_image_call > fork()s then waits in blocking read() for the input from the child > process, but child finishes its tasks and exits, thus emitting SIGCHLD > signal which then leads to the interruption of the blocking read() in > the parent process with EINTR error. > > It seems like the recent fixes in the libubox library, particulary in > the jshn sub-component (which empowers json_dump used in the shell > script executed by the child process) made the execution somehow faster, > thus exposing this racy behaviour in the validate_firmware_image_call at > least on RPi-4 (Cortex-A72) target. > > So this patch fixes this issue by checking the read() return value and > retrying the read() if interrupted due to the EINTR error. > > Ref: http://lists.infradead.org/pipermail/openwrt-devel/2020-January/020994.html > Fixes: e990e215e8a3 ("system: add "validate_firmware_image" ubus method") > Cc: Rafał Miłecki <rafal@milecki.pl> > Reported-by: Petr Novák <petrn@me.com> > Signed-off-by: Petr Štetiar <ynezz@true.cz> > --- Reviewed-by: Hauke Mehrtens <hauke@hauke-m.de> > system.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/system.c b/system.c > index 65d3f09b7fb6..5cd88e0d8227 100644 > --- a/system.c > +++ b/system.c > @@ -466,6 +466,9 @@ static int validate_firmware_image_call(const char *file) > > blob_buf_init(&b, 0); > while ((len = read(fds[0], buf, sizeof(buf)))) { > + if (len < 0 && errno == EINTR) > + continue; > + > jsobj = json_tokener_parse_ex(tok, buf, len); > > if (json_tokener_get_error(tok) == json_tokener_success) > > _______________________________________________ > openwrt-devel mailing list > openwrt-devel@lists.openwrt.org > https://lists.openwrt.org/mailman/listinfo/openwrt-devel >
diff --git a/system.c b/system.c index 65d3f09b7fb6..5cd88e0d8227 100644 --- a/system.c +++ b/system.c @@ -466,6 +466,9 @@ static int validate_firmware_image_call(const char *file) blob_buf_init(&b, 0); while ((len = read(fds[0], buf, sizeof(buf)))) { + if (len < 0 && errno == EINTR) + continue; + jsobj = json_tokener_parse_ex(tok, buf, len); if (json_tokener_get_error(tok) == json_tokener_success)
It was quite common to see following error during sysupgrade on serial console: Failed to parse JSON: 4 This is happening due to the fact, that validate_firmware_image_call fork()s then waits in blocking read() for the input from the child process, but child finishes its tasks and exits, thus emitting SIGCHLD signal which then leads to the interruption of the blocking read() in the parent process with EINTR error. It seems like the recent fixes in the libubox library, particulary in the jshn sub-component (which empowers json_dump used in the shell script executed by the child process) made the execution somehow faster, thus exposing this racy behaviour in the validate_firmware_image_call at least on RPi-4 (Cortex-A72) target. So this patch fixes this issue by checking the read() return value and retrying the read() if interrupted due to the EINTR error. Ref: http://lists.infradead.org/pipermail/openwrt-devel/2020-January/020994.html Fixes: e990e215e8a3 ("system: add "validate_firmware_image" ubus method") Cc: Rafał Miłecki <rafal@milecki.pl> Reported-by: Petr Novák <petrn@me.com> Signed-off-by: Petr Štetiar <ynezz@true.cz> --- system.c | 3 +++ 1 file changed, 3 insertions(+)