On 6/21/23 23:00, Christoph Hellwig wrote:
Hi Guenter,
can you try this patch?
diff --git a/block/early-lookup.c b/block/early-lookup.c
index a5be3c68ed079c..66e4514d671179 100644
--- a/block/early-lookup.c
+++ b/block/early-lookup.c
@@ -174,7 +174,7 @@ static int __init devt_from_devname(const char *name, dev_t *devt)
while (p > s && isdigit(p[-1]))
p--;
if (p == s || !*p || *p == '0')
- return -EINVAL;
+ return -ENODEV;
/* try disk name without <part number> */
part = simple_strtoul(p, NULL, 10);
Not completely. Tests with root=/dev/sda still fail.
"name" passed to devt_from_devname() is "sda".
for (p = s; *p; p++) {
if (*p == '/')
*p = '!';
}
advances 'p' to the end of the string.
while (p > s && isdigit(p[-1]))
p--;
moves it back to point to the first digit (if there is one).
if (p == s || !*p || *p == '0')
return -EINVAL;
then fails because *p is 0. In other words, the function only accepts
drive names with digits at the end (and the first digit must not be '0').
I don't recall how I hit the other condition earlier. I have various
"/dev/mmcblkX" in my tests, where X can be any number including 0.
Maybe those fail randomly as well.
Overall I am not sure though what an "invalid" devicename is supposed
to be in this context. I have "sda", "sr0", "vda", "mtdblkX",
"nvme0n1", "mmcblkX", and "hda". Why would any of those not be eligible
for "rootwait" ?
In practice, everything not ending with a digit, or ending with
'0', fails the first test. Everything ending with a digit > 0
fails the second test. But "humptydump3p4" passes all those tests.
Guenter
---
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#define EINVAL1 1
#define EINVAL2 2
#define EINVAL3 3
#define ENODEV 4
static int devt_from_devname(const char *name)
{
int part;
char s[32];
char *p;
if (strlen(name) > 31)
return EINVAL1;
strcpy(s, name);
for (p = s; *p; p++) {
if (*p == '/')
*p = '!';
}
/*
* Try non-existent, but valid partition, which may only exist after
* opening the device, like partitioned md devices.
*/
while (p > s && isdigit(p[-1]))
p--;
if (p == s || !*p || *p == '0') {
return EINVAL2;
}
/* try disk name without <part number> */
part = strtoul(p, NULL, 10);
*p = '\0';
/* try disk name without p<part number> */
if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') {
return EINVAL3;
}
return ENODEV;
}
char *devnames[] = {
"sda",
"sda1",
"mmcblk0",
"mmcblk1",
"mtdblk0",
"mtdblk1",
"vda",
"hda",
"nvme0n1",
"sr0",
"sr1",
"humptydump3p4",
NULL
};
int main(int argc, char **argv)
{
char *str;
int i;
for (i = 0, str = devnames[0]; str; str = devnames[++i]) {
printf("%s: %d\n", str, devt_from_devname(str));
}
}
