On Tuesday February 6, g944370@xxxxxxxxxxxxxx wrote: > Hi all, > I write a module that creates a kernel thread to show the BIOs from > MD modules. > The kernel thread will call show_bio() when md passing a BIO to my > module,else sleep. > Sometimes, show_bio() continues working successfully ,but it > somtimes makes "general protection fault". > The show_bio() always works when I comment the > "bio_for_each_segment" loop. > Is the zone I comment the cause of the fault? > As above, I consider it's the main problem.Also, I strongly want to > know your opinions.Thank you for help. > > THX Without seeing how the bio gets to show_bio it is hard to be certain, but my guess would be that by the time show_bio tries to inspect the bio, the IO request involving it has already completed and the bio has been freed, so you are accessing freed memory. > Feb 6 22:00:28 RAID-SUSE kernel: Code: 8b 00 f6 c4 08 74 0e 48 c7 c7 14 9c > 45 88 31 c0 e8 b5 bf e2 If you feed this line into ksymoops you get: Code; 0000000000000000 Before first symbol 0: 8b 00 mov (%rax),%eaxC ... so it is trying to dereference $rax. > Feb 6 22:00:28 RAID-SUSE kernel: RAX: 6b6b6b6b6b6b6b6b RBX: > ffff810037f52668 RCX: 0000000000040000 Which contains 6b6b6b6b6b6b6b6b. which is lots of copies of 'POISON_FREE' (defined in include/linux/poison.h) which makes it really look like that memory has already been freed. NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
