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authorNicholas Bellinger <nab@linux-iscsi.org>2014-01-29 02:56:30 +0100
committerNicholas Bellinger <nab@linux-iscsi.org>2014-01-30 12:58:34 +0100
commit5259a06ef97068b710f45d092a587e8d740f750f (patch)
treeda2b4c9718b41cec6e5057a3da593cc93c44759c /lib
parenttarget/iscsi: Fix network portal creation race (diff)
downloadlinux-5259a06ef97068b710f45d092a587e8d740f750f.tar.xz
linux-5259a06ef97068b710f45d092a587e8d740f750f.zip
target: Fix percpu_ref_put race in transport_lun_remove_cmd
This patch fixes a percpu_ref_put race for se_lun->lun_ref in transport_lun_remove_cmd() where ->lun_ref could end up being put more than once per command via different target completion and fabric release contexts. It adds a cmpxchg() for se_cmd->lun_ref_active to ensure that percpu_ref_put() is only ever called once per se_cmd. This bug was manifesting itself as a LUN shutdown regression bug in >= v3.13 code, where percpu_ref_kill() would end up hanging indefinately due to the incorrect percpu_ref count. (Change se_cmd->lun_ref_active from bool -> int to force at least a 4-byte cmpxchg with MIPS ll/sc ins. - Fengguang) Reported-by: Tommy Apel <tommyapeldk@gmail.com> Cc: Tommy Apel <tommyapeldk@gmail.com> Cc: <stable@vger.kernel.org> #3.13+ Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'lib')
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