On Mon, 9 Dec 2013 02:54:44 +0900
Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx> wrote:
> The tgt_device_destroy function arises segmentation fault if we delete
> a target with a force option while an iscsi session exists:
>
> kernel: tgtd[10094]: segfault at 7fe2511b1b4f ip 0000000000414080
> sp 00007fff9f2df0e0 error 4 in tgtd[400000+33000]
> tgtd: tgtd logger exits abnormally, pid:10095
>
> This fault is reproducible with the following steps:
>
> server# dog vdi create <vdiname> 10G
> server# tgtadm --lld iscsi --mode target --op new --tid 1 -T <target>
> server# tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1
> --backing-store unix:/sheepdog/sock:<vdiname> --bstype sheepdog
> server# tgtadm --lld iscsi --mode account --op new --user <user>
> --password <password>
> server# tgtadm --lld iscsi --mode account --op bind --tid 1 --user <user>
> server# tgtadm --lld iscsi --mode target --op bind --tid 1 -I ALL
>
> client# iscsiadm -m discovery -t sendtargets -p <server ip>
> client# iscsiadm -m node -T <target> --op update --name
> node.session.auth.authmethod --value CHAP
> client# iscsiadm -m node -T <target> --op update --name
> node.session.auth.username --value <user>
> client# iscsiadm -m node -T <target> --op update --name
> node.session.auth.password --value <password>
> client# iscsiadm -m node -T <target> --login
>
> server# tgtadm --lld iscsi --mode target --op delete --force --tid 1
>
> The backtrace of the fault is as follows:
>
> # gdb tgtd /core.10094
> Program terminated with signal 11, Segmentation fault.
> #0 0x0000000000414080 in ua_sense_add (itn_lu=0x1288a30, asc=16142)
> at target.c:108
> 108 if (itn_lu->lu->attrs.sense_format) {
> (gdb) bt
> #0 0x0000000000414080 in ua_sense_add (itn_lu=0x1288a30, asc=16142)
> at target.c:108
> #1 0x00000000004143d5 in tgt_device_destroy (tid=<value optimized out>,
> lun=<value optimized out>, force=<value optimized out>) at target.c:731
> #2 0x0000000000414554 in tgt_target_destroy (lld_no=0, tid=1, force=1)
> at target.c:2000
> #3 0x0000000000412161 in target_mgmt (mtask=0x1288a70) at mgmt.c:87
> #4 tgt_mgmt (mtask=0x1288a70) at mgmt.c:412
> #5 0x0000000000412777 in mtask_handler (fd=13, events=<value optimized out>,
> data=0x1288a70) at mgmt.c:492
> #6 0x00000000004106a9 in event_loop () at tgtd.c:411
> #7 0x0000000000410d65 in main (argc=<value optimized out>,
> argv=<value optimized out>) at tgtd.c:583
>
> The fault happened because the current tgt_device_destroy function
> does not remove nor free it_nexus_lu_info structures associated to the
> lun that we are deleting.
>
> Due to the leak, ua_sense_add function accesses to the lun info
> (itn_lu->lun) that is already freed.
>
> I here used a sheepdog backing store, but the same issue can happen
> for other types of backing store.
>
> This patch fixes the issue by adding missing cleanup code of
> it_nexus_lu_info struct to tgt_device_destroy function.
>
> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
> ---
> usr/target.c | 4 ++++
> 1 file changed, 4 insertions(+)
Looks good, thanks a lot!
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