• Javed Hasan's avatar
    scsi: libfc: Skip additional kref updating work event · 4575845e
    Javed Hasan authored
    [ Upstream commit 823a6540 ]
    
    When an rport event (RPORT_EV_READY) is updated without work being queued,
    avoid taking an additional reference.
    
    This issue was leading to memory leak. Trace from KMEMLEAK tool:
    
      unreferenced object 0xffff8888259e8780 (size 512):
      comm "kworker/2:1", jiffies 4433237386 (age 113021.971s)
        hex dump (first 32 bytes):
    	58 0a ec cf 83 88 ff ff 00 00 00 00 00 00 00 00
    	01 00 00 00 08 00 00 00 13 7d f0 1e 0e 00 00 10
      backtrace:
      [<000000006b25760f>] fc_rport_recv_req+0x3c6/0x18f0 [libfc]
      [<00000000f208d994>] fc_lport_recv_els_req+0x120/0x8a0 [libfc]
      [<00000000a9c437b8>] fc_lport_recv+0xb9/0x130 [libfc]
      [<00000000a9c437b8>] fc_lport_recv+0xb9/0x130 [libfc]
      [<00000000ad5be37b>] qedf_ll2_process_skb+0x73d/0xad0 [qedf]
      [<00000000e0eb6893>] process_one_work+0x382/0x6c0
      [<000000002dfd9e21>] worker_thread+0x57/0x5c0
      [<00000000b648204f>] kthread+0x1a0/0x1c0
      [<0000000072f5ab20>] ret_from_fork+0x35/0x40
      [<000000001d5c05d8>] 0xffffffffffffffff
    
    Below is the log sequence which leads to memory leak.  Here we get the
    RPORT_EV_READY and RPORT_EV_STOP back to back, which lead to overwrite the
    event RPORT_EV_READY by event RPORT_EV_STOP.  Because of this, kref_count
    gets incremented by 1.
    
      kernel: host0: rport fffce5: Received PLOGI request
      kernel: host0: rport fffce5: Received PLOGI in INIT state
      kernel: host0: rport fffce5: Port is Ready
      kernel: host0: rport fffce5: Received PRLI request while in state Ready
      kernel: host0: rport fffce5: PRLI rspp type 8 active 1 passive 0
      kernel: host0: rport fffce5: Received LOGO request while in state Ready
      kernel: host0: rport fffce5: Delete port
      kernel: host0: rport fffce5: Received PLOGI request
      kernel: host0: rport fffce5: Received PLOGI in state Delete - send busy
      kernel: host0: rport fffce5: work event 3
      kernel: host0: rport fffce5: lld callback ev 3
      kernel: host0: rport fffce5: work delete
    
    Link: https://lore.kernel.org/r/20200626094959.32151-1-jhasan@marvell.comReviewed-by: default avatarGirish Basrur <gbasrur@marvell.com>
    Reviewed-by: default avatarSaurav Kashyap <skashyap@marvell.com>
    Reviewed-by: default avatarShyam Sundar <ssundar@marvell.com>
    Signed-off-by: default avatarJaved Hasan <jhasan@marvell.com>
    Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    4575845e
fc_rport.c 60.3 KB