On Fri, 16 Mar 2012, Jan Kara wrote: > > CPU is a Core i3 530, on a Gigabyte motherbord, 4 GB RAM. No ECC, > > unfortunately, so I can't rule out hardware bit rot. Distribution is > > a fairly stock Debian/unstable. > Hmm, is any mounting & unmounting happening during your backup? Because > the oops happened because sb->s_fs_info was NULL. Dissassembly shows: > 16: 48 8b 47 18 mov 0x18(%rdi),%rax > store sb->s_blocksize into RAX > 1a: 48 8b 8f b0 02 00 00 mov 0x2b0(%rdi),%rcx > store sb->s_fs_info into RCX > 21: 48 c1 e8 02 shr $0x2,%rax > This is division from EXT3_ADDR_PER_BLOCK() - RAX carries 1024 after > division so that looks correct. > > 25: 48 85 db test %rbx,%rbx > Now check passed i_block argument. > > 28: 41 89 c4 mov %eax,%r12d > 2b:* 8b b1 94 00 00 00 mov 0x94(%rcx),%esi <-- trapping ins > Try to get RCX->s_addr_per_block_bits... > > sb->s_fs_info is set when a superblock is mounted and cleared when > superblock gets unmounted and otherwise it is never changed. So most likely > it was some memory corruption clearing that pointer (I wouldn't really > suspect HW here). > > It somewhat looks like the issue described here: > http://lkml.indiana.edu/hypermail/linux/kernel/1202.3/00132.html > > Although there we had f_path.dentry (completely different structure) being > NULL. But similarity here is that something stomped NULL over our existing > structure. > > Linus, Jiri, that bug didn't get resolved, did it? I am not aware of anything, but I have a question -- George, did the machine get suspended/resumed before this happened? -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
