When using the LV_BMAP ioctl with an out-of-range block number, the
kernel oopes in drviers/md/lvm.c:lvm_map().
The check in lvm_map() for out-of-range sector number works correctly,
and the corresponding message is written to the kernel logs.
if (rsector_org + size > lv->lv_size) {
printk(KERN_ALERT
"%s - lvm_map access beyond end of device; *rsector: "
"%lu or size: %lu wrong for minor: %2d\n",
lvm_name, rsector_org, size, minor);
goto bad;
}
After the "goto bad;" the Oops seems to be buffer_IO_error(bh).
bad:
buffer_IO_error(bh);
up_read(&lv->lv_lock);
return -1;
When using the LV_BMAP ioctl, lvm_map is called from lvm_user_bmap(),
to which the system call does not return because of the oops.
if ((err=lvm_map(&bh, READ)) < 0) {
printk("lvm map failed: %d\n", err);
return -EINVAL;
}
The "lvm map failed..." error message is not logged.
Here is the oops from the kernel. It was produced by ioctl(LV_BMAP)
on a LV of 128MB (262144) sectors, with lbm.lv_block = 131072.
isnogud kernel: lvm - lvm_map access beyond end of device; *rsector: 262144 or size: 2 wrong for minor: 0
isnogud kernel: Unable to handle kernel NULL pointer dereference at virtual address 00000000
isnogud kernel: printing eip:
isnogud kernel: 00000000
isnogud kernel: *pde = 00000000
isnogud kernel: Oops: 0000
isnogud kernel: CPU: 0
isnogud kernel: EIP: 0010:[<00000000>] Not tainted
isnogud kernel: EFLAGS: 00010246
isnogud kernel: eax: 00000000 ebx: c939df00 ecx: c939c000 edx: c939df00
isnogud kernel: esi: 00000000 edi: c939df60 ebp: c939df00 esp: c939de9c
isnogud kernel: ds: 0018 es: 0018 ss: 0018
isnogud kernel: Process lvm-map (pid: 18809, stackpage=c939d000)
isnogud kernel: Stack: d0836640 c939df00 00000000 bffffad4 00040000 c939df60 c939df00 cf9ae2c0
isnogud kernel: ca4c3820 cf9f2400 cf949000 400f0000 00000000 400f0550 cc6baca0 00000000
isnogud kernel: c903a960 d08360ab c939df00 00000000 00003a00 bffffad4 00003a00 c3c94060
isnogud kernel: Call Trace: [8139too:__insmod_8139too_O/lib/modules/2.4.17-ut/kernel/drivers/net+-780736/96] [8139too:__insmod_8139too_O/lib/modules/2.4.17-ut/kernel/drivers/net+-782165/96] [8139too:__insmod_8139too_O/lib/modules/2.4.17-ut/kernel/drivers/net+-782740/96] [blkdev_ioctl+40/52] [sys_ioctl+363/388]
isnogud kernel: [system_call+51/56]
isnogud kernel:
isnogud kernel: Code: Bad EIP value.
urs
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