From: Sam Bobroff Date: Fri, 7 Feb 2020 04:57:31 +0000 (+1100) Subject: powerpc/eeh: Fix deadlock handling dead PHB X-Git-Tag: v5.4.23~93 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a03b3cea86fdaf9a1cc57925e6dd9ddc28a6f4a5;p=platform%2Fkernel%2Flinux-rpi.git powerpc/eeh: Fix deadlock handling dead PHB commit d4f194ed9eb9841a8f978710e4d24296f791a85b upstream. Recovering a dead PHB can currently cause a deadlock as the PCI rescan/remove lock is taken twice. This is caused as part of an existing bug in eeh_handle_special_event(). The pe is processed while traversing the PHBs even though the pe is unrelated to the loop. This causes the pe to be, incorrectly, processed more than once. Untangling this section can move the pe processing out of the loop and also outside the locked section, correcting both problems. Fixes: 2e25505147b8 ("powerpc/eeh: Fix crash when edev->pdev changes") Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Sam Bobroff Reviewed-by: Frederic Barrat Tested-by: Frederic Barrat Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0547e82dbf90ee0729a2979a8cac5c91665c621f.1581051445.git.sbobroff@linux.ibm.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c index 2fb1669..4fd7efd 100644 --- a/arch/powerpc/kernel/eeh_driver.c +++ b/arch/powerpc/kernel/eeh_driver.c @@ -1200,6 +1200,17 @@ void eeh_handle_special_event(void) eeh_pe_state_mark(pe, EEH_PE_RECOVERING); eeh_handle_normal_event(pe); } else { + eeh_for_each_pe(pe, tmp_pe) + eeh_pe_for_each_dev(tmp_pe, edev, tmp_edev) + edev->mode &= ~EEH_DEV_NO_HANDLER; + + /* Notify all devices to be down */ + eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true); + eeh_set_channel_state(pe, pci_channel_io_perm_failure); + eeh_pe_report( + "error_detected(permanent failure)", pe, + eeh_report_failure, NULL); + pci_lock_rescan_remove(); list_for_each_entry(hose, &hose_list, list_node) { phb_pe = eeh_phb_pe_get(hose); @@ -1208,16 +1219,6 @@ void eeh_handle_special_event(void) (phb_pe->state & EEH_PE_RECOVERING)) continue; - eeh_for_each_pe(pe, tmp_pe) - eeh_pe_for_each_dev(tmp_pe, edev, tmp_edev) - edev->mode &= ~EEH_DEV_NO_HANDLER; - - /* Notify all devices to be down */ - eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true); - eeh_set_channel_state(pe, pci_channel_io_perm_failure); - eeh_pe_report( - "error_detected(permanent failure)", pe, - eeh_report_failure, NULL); bus = eeh_pe_bus_get(phb_pe); if (!bus) { pr_err("%s: Cannot find PCI bus for "