Messages in this thread Patch in this message |  | | From | Joachim Weller <> | Subject | BUG: cat /proc/partitions endless loop | Date | Fri, 28 Sep 2001 15:15:51 +0200 |
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After upgrading from 2.4.9 to 2.4.10, I discovered that a "cat /proc/partitions" resulted in an infinite repetition of the partition list. This resulted in a complete hang of SuSE's sys admin tool yast. A more detailed report was sent to Jens Axboe (axboe@suse.de)
The affected machine is a dual pentium pro: Linux version 2.4.10 (root@bmdipc2c) (gcc version 2.95.3 20010315 (SuSE)) #1 SMP Fri Sep 28 13:10:18 CEST 2001
I traced the problem down to drivers/block/genhd.c, where the function get_partition_list() outer loop does not terminate due to the last element in the structured list starting with gendisk_head is not initialized to NULL, by whatever reason. My fix does not cure the pointered endless loop, but prevents from looping when stepping thru the pointered list. -------------------------------------------------------------------------------------- diff -u --recursive --new-file 2.4.10/linux/drivers/block/genhd.c linux/drivers/block/genhd.c --- 2.4.10/linux/drivers/block/genhd.c Sun Sep 9 21:00:55 2001 +++ linux/drivers/block/genhd.c Fri Sep 28 14:45:13 2001 @@ -14,6 +14,15 @@ * TODO: rip out the remaining init crap from this file --hch */
+/* + * Change: Blocked potential endless loop within get_partition_list() + * which occured for "cat /proc/partitions" + * because gendisk_head->next is not initialized correctly to NULL + * before add_gendisk() is called the first time. + * Joachim Weller 28sep2001 (JoachimWeller@web.de) + * + */ + #include <linux/config.h> #include <linux/module.h> #include <linux/fs.h> @@ -115,7 +124,7 @@
len = sprintf(page, "major minor #blocks name\n\n"); read_lock(&gendisk_lock); - for (gp = gendisk_head; gp; gp = gp->next) { + for (gp = gendisk_head; gp; gp = (gp->next!=gendisk_head ? gp->next : NULL)) { for (n = 0; n < (gp->nr_real << gp->minor_shift); n++) { if (gp->part[n].nr_sects == 0) continue; -------------------------------------------------------------------------------------- -- Joachim Weller
Philips Medizinsysteme Boeblingen GmbH Mail: joachim_weller@hsgmed.com Cardiac and Monitoring Systems (CMS) Phone: {+49|0}-7031-463-1891 New Product Engineering Fax: {+49|0}-7031-463-2112 Hewlett-Packard Str. 2, D 71034 Boeblingen -GERMANY-
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