5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Quinn Tran <qutran@xxxxxxxxxxx> commit 07c903db0a2ff84b68efa1a74a4de353ea591eb0 upstream. System crash is observed with stack trace warning of use after free. There are 2 signals to tell dpc_thread to terminate (UNLOADING flag and kthread_stop). On setting the UNLOADING flag when dpc_thread happens to run at the time and sees the flag, this causes dpc_thread to exit and clean up itself. When kthread_stop is called for final cleanup, this causes use after free. Remove UNLOADING signal to terminate dpc_thread. Use the kthread_stop as the main signal to exit dpc_thread. [596663.812935] kernel BUG at mm/slub.c:294! [596663.812950] invalid opcode: 0000 [#1] SMP PTI [596663.812957] CPU: 13 PID: 1475935 Comm: rmmod Kdump: loaded Tainted: G IOE --------- - - 4.18.0-240.el8.x86_64 #1 [596663.812960] Hardware name: HP ProLiant DL380p Gen8, BIOS P70 08/20/2012 [596663.812974] RIP: 0010:__slab_free+0x17d/0x360 ... [596663.813008] Call Trace: [596663.813022] ? __dentry_kill+0x121/0x170 [596663.813030] ? _cond_resched+0x15/0x30 [596663.813034] ? _cond_resched+0x15/0x30 [596663.813039] ? wait_for_completion+0x35/0x190 [596663.813048] ? try_to_wake_up+0x63/0x540 [596663.813055] free_task+0x5a/0x60 [596663.813061] kthread_stop+0xf3/0x100 [596663.813103] qla2x00_remove_one+0x284/0x440 [qla2xxx] Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Quinn Tran <qutran@xxxxxxxxxxx> Signed-off-by: Nilesh Javali <njavali@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20241115130313.46826-3-njavali@xxxxxxxxxxx Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/scsi/qla2xxx/qla_os.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) --- a/drivers/scsi/qla2xxx/qla_os.c +++ b/drivers/scsi/qla2xxx/qla_os.c @@ -6851,12 +6851,15 @@ qla2x00_do_dpc(void *data) set_user_nice(current, MIN_NICE); set_current_state(TASK_INTERRUPTIBLE); - while (!kthread_should_stop()) { + while (1) { ql_dbg(ql_dbg_dpc, base_vha, 0x4000, "DPC handler sleeping.\n"); schedule(); + if (kthread_should_stop()) + break; + if (test_and_clear_bit(DO_EEH_RECOVERY, &base_vha->dpc_flags)) qla_pci_set_eeh_busy(base_vha); @@ -6869,15 +6872,16 @@ qla2x00_do_dpc(void *data) goto end_loop; } + if (test_bit(UNLOADING, &base_vha->dpc_flags)) + /* don't do any work. Wait to be terminated by kthread_stop */ + goto end_loop; + ha->dpc_active = 1; ql_dbg(ql_dbg_dpc + ql_dbg_verbose, base_vha, 0x4001, "DPC handler waking up, dpc_flags=0x%lx.\n", base_vha->dpc_flags); - if (test_bit(UNLOADING, &base_vha->dpc_flags)) - break; - if (IS_P3P_TYPE(ha)) { if (IS_QLA8044(ha)) { if (test_and_clear_bit(ISP_UNRECOVERABLE, @@ -7195,9 +7199,6 @@ end_loop: */ ha->dpc_active = 0; - /* Cleanup any residual CTX SRBs. */ - qla2x00_abort_all_cmds(base_vha, DID_NO_CONNECT << 16); - return 0; }
