Re: Linux 4.19.154

Jari Ruusu
2020-10-31T13:30:54Z

Greg Kroah-Hartman wrote:
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -2127,11 +2127,10 @@ static void handle_bad_sector(struct bio *bio, sector_t maxsector)
> {
> char b[BDEVNAME_SIZE];
>
> - printk(KERN_INFO "attempt to access beyond end of device\n");
> - printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n",
> - bio_devname(bio, b), bio->bi_opf,
> - (unsigned long long)bio_end_sector(bio),
> - (long long)maxsector);
> + pr_info_ratelimited("attempt to access beyond end of device\n"
> + "%s: rw=%d, want=%llu, limit=%llu\n",
> + bio_devname(bio, b), bio->bi_opf,
> + bio_end_sector(bio), maxsector);
> }
>
> #ifdef CONFIG_FAIL_MAKE_REQUEST

Above change "block: ratelimit handle_bad_sector() message"
upstream commit f4ac712e4fe009635344b9af5d890fe25fcc8c0d
in 4.19.154 kernel is not completely OK.

Removing casts from arguments 4 and 5 produces these compile warnings:

In file included from ./include/linux/kernel.h:14:0,
from block/blk-core.c:14:
block/blk-core.c: In function 'handle_bad_sector':
./include/linux/kern_levels.h:5:18: warning: format '%llu' expects argument of type 'long long unsigned int', but argument 4 has type 'sector_t {aka long unsigned int}' [-Wformat=]
#define KERN_SOH "\001" /* ASCII Start Of Header */
^
./include/linux/printk.h:424:10: note: in definition of macro 'printk_ratelimited'
printk(fmt, ##__VA_ARGS__); \
^~~
./include/linux/kern_levels.h:14:19: note: in expansion of macro 'KERN_SOH'
#define KERN_INFO KERN_SOH "6" /* informational */
^~~~~~~~
./include/linux/printk.h:444:21: note: in expansion of macro 'KERN_INFO'
printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
^~~~~~~~~
block/blk-core.c:2130:2: note: in expansion of macro 'pr_info_ratelimited'
pr_info_ratelimited("attempt to access beyond end of device\n"
^~~~~~~~~~~~~~~~~~~
./include/linux/kern_levels.h:5:18: warning: format '%llu' expects argument of type 'long long unsigned int', but argument 5 has type 'sector_t {aka long unsigned int}' [-Wformat=]
#define KERN_SOH "\001" /* ASCII Start Of Header */
^
./include/linux/printk.h:424:10: note: in definition of macro 'printk_ratelimited'
printk(fmt, ##__VA_ARGS__); \
^~~
./include/linux/kern_levels.h:14:19: note: in expansion of macro 'KERN_SOH'
#define KERN_INFO KERN_SOH "6" /* informational */
^~~~~~~~
./include/linux/printk.h:444:21: note: in expansion of macro 'KERN_INFO'
printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
^~~~~~~~~
block/blk-core.c:2130:2: note: in expansion of macro 'pr_info_ratelimited'
pr_info_ratelimited("attempt to access beyond end of device\n"
^~~~~~~~~~~~~~~~~~~

For 64 bit systems it is only compile time cosmetic warning. For 32 bit
system + CONFIG_LBDAF=n it introduces bugs: output formats are "%llu" and
passed parameters are 32 bits. That is not OK.

Upstream kernels have hardcoded 64 bit sector_t. In older stable trees
sector_t can be either 64 or 32 bit. In other words, backport of above patch
needs to keep those original casts.

--
Jari Ruusu 4096R/8132F189 12D6 4C3A DCDA 0AA4 27BD ACDF F073 3C80 8132 F189