> +#define DM_MSG_PREFIX "unstriped"
> +
> +void cleanup_unstripe(struct unstripe_c *uc, struct dm_target *ti)
> +{
> + if (uc->dev)
> + dm_put_device(ti, uc->dev);
> + kfree(uc);
> +}
> +
> +/*
> + * Contruct an unstriped mapping.
> + * <number of stripes> <chunk size> <stripe #> <dev_path> <offset>
> + */
> +static int unstripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
> +{
[snip]
> + tmp_len = width;
> + if (sector_div(tmp_len, uc->chunk_size)) {
> + ti->error = "Target length not divisible by chunk size";
> + goto err;
> + }
> +
> + r = dm_set_target_max_io_len(ti, uc->chunk_size);
> + if (r) {
> + ti->error = "Failed to set max io len";
> + goto err;
> + }
> +
> + ti->private = uc;
> + return 0;
> +err:
> + cleanup_unstripe(uc, ti);
> + return r;
> +}
[snip]
> +static int unstripe_iterate_devices(struct dm_target *ti,
> + iterate_devices_callout_fn fn, void *data)
> +{
> + struct unstripe_c *uc = ti->private;
> +
> + return fn(ti, uc->dev, uc->physical_start, ti->len, data);
> +}
I was testing some error conditions:
#1 set up legitimate unstripe.
#2 remove it.
#3 set up an unstripe that fails the
> + tmp_len = width;
> + if (sector_div(tmp_len, uc->chunk_size)) {
> + ti->error = "Target length not divisible by chunk size";
> + goto err;
> + }
check in the constructor (so give it an odd length):
I'm greeted by this splat:
[ 76.349033] BUG: unable to handle kernel NULL pointer dereference at 0000000066b57171
[ 76.349051] IP: unstripe_iterate_devices+0x13/0x20 [dm_unstripe]
[ 76.349055] PGD 0 P4D 0
[ 76.349062] Oops: 0000 [#1] SMP
[ 76.349065] Modules linked in: dm_unstripe binfmt_misc nls_iso8859_1 snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec intel_rapl x86_pkg_temp_thermal snd_hda_core intel_powerclamp kvm_intel snd_hwdep snd_pcm kvm snd_seq_midi snd_seq_midi_event snd_rawmidi irqbypass crct10dif_pclmul snd_seq crc32_pclmul ghash_clmulni_intel pcbc snd_seq_device snd_timer aesni_intel snd mei_me aes_x86_64 crypto_simd glue_helper cryptd shpchp mei soundcore mac_hid tpm_crb acpi_pad coretemp parport_pc ppdev lp parport ip_tables x_tables autofs4 hid_generic usbhid hid i915 drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm igb mxm_wmi e1000e dca ptp ahci pps_core i2c_algo_bit libahci video wmi
[ 76.349153] CPU: 2 PID: 1688 Comm: dmsetup Not tainted 4.15.0-rc2+ #7
[ 76.349157] Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016
[ 76.349160] task: 00000000dfd78dfc task.stack: 00000000fadda433
[ 76.349166] RIP: 0010:unstripe_iterate_devices+0x13/0x20 [dm_unstripe]
[ 76.349169] RSP: 0018:ffffb89842d13c00 EFLAGS: 00010286
[ 76.349173] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000001749c7ff
[ 76.349176] RDX: ffffb89842d13c0c RSI: ffffffff902ad590 RDI: ffffb89841ed1040
[ 76.349179] RBP: ffffffff902ad590 R08: ffffb89842d13c0c R09: ffffffff902ad590
[ 76.349182] R10: ffffb89842d13c68 R11: ffffa020daef0000 R12: ffffa0208ec63600
[ 76.349184] R13: 0000000000000001 R14: ffffffff902b29a0 R15: ffffb89842d13d20
[ 76.349189] FS: 00007faa3ee63400(0000) GS:ffffa020f1c80000(0000) knlGS:0000000000000000
[ 76.349192] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 76.349195] CR2: 0000000000000008 CR3: 000000045c342004 CR4: 00000000003606e0
[ 76.349200] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 76.349203] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 76.349205] Call Trace:
[ 76.349217] dm_table_has_no_data_devices+0x91/0xc0
[ 76.349225] dm_swap_table+0x6b/0x2e0
[ 76.349230] ? table_load+0x350/0x350
[ 76.349234] ? __dm_suspend+0x7c/0x1d0
[ 76.349239] ? table_load+0x350/0x350
[ 76.349243] dev_suspend+0x95/0x220
[ 76.349247] ctl_ioctl+0x1bf/0x450
[ 76.349257] ? yield_to+0x130/0x1b0
[ 76.349261] dm_ctl_ioctl+0xa/0x10
[ 76.349268] do_vfs_ioctl+0x9f/0x5f0
[ 76.349274] ? SYSC_semctl+0xf9/0x130
[ 76.349279] ? _cond_resched+0x16/0x40
[ 76.349285] ? task_work_run+0x38/0xa0
[ 76.349291] SyS_ioctl+0x74/0x80
[ 76.349296] entry_SYSCALL_64_fastpath+0x1e/0x81
[ 76.349301] RIP: 0033:0x7faa3e766587
[ 76.349304] RSP: 002b:00007ffcba093b88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 76.349309] RAX: ffffffffffffffda RBX: 000000000d4d1614 RCX: 00007faa3e766587
[ 76.349312] RDX: 0000563b73da7190 RSI: 00000000c138fd06 RDI: 0000000000000003
[ 76.349314] RBP: 0000000000000004 R08: 00007faa3ea72ba8 R09: 00007ffcba0939f0
[ 76.349317] R10: 00007faa3ea720b3 R11: 0000000000000246 R12: 0000563b72eb1190
[ 76.349320] R13: 00007ffcba093f14 R14: 00007ffcba093ebc R15: 0000000000018000
[ 76.349324] Code: <48> 8b 50 08 48 8b 30 41 ff e1 0f 1f 00 0f 1f 44 00 00 48 8b 47 38
[ 76.349359] RIP: unstripe_iterate_devices+0x13/0x20 [dm_unstripe] RSP: ffffb89842d13c00
[ 76.349362] CR2: 0000000000000008
[ 76.349366] ---[ end trace f92285c94fd36893 ]---
Two questions:
Do we need to set ti-private = NULL in "cleanup_unstripe"? Also, do we
need to have :
static int unstripe_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
struct unstripe_c *uc = ti->private;
if (uc)
return fn(ti, uc->dev, uc->physical_start, ti->len, data);
}
~
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
