4.16-stable review patch. If anyone has any objections, please let me know.
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From: Mahesh Salgaonkar mahesh@linux.vnet.ibm.com
commit 75ecfb49516c53da00c57b9efe48fa3f5504a791 upstream.
The current code extracts the physical address for UE errors and then hooks it up into memory failure infrastructure. On successful extraction of physical address it wrongly sets "handled = 1" which means this UE error has been recovered. Since MCE handler gets return value as handled = 1, it assumes that error has been recovered and goes back to same NIP. This causes MCE interrupt again and again in a loop leading to hard lockup.
Also, initialize phys_addr to ULONG_MAX so that we don't end up queuing undesired page to hwpoison.
Without this patch we see: Severe Machine check interrupt [Recovered] NIP: [000000001002588c] PID: 7109 Comm: find Initiator: CPU Error type: UE [Load/Store] Effective address: 00007fffd2755940 Physical address: 000020181a080000 ... Severe Machine check interrupt [Recovered] NIP: [000000001002588c] PID: 7109 Comm: find Initiator: CPU Error type: UE [Load/Store] Effective address: 00007fffd2755940 Physical address: 000020181a080000 Severe Machine check interrupt [Recovered] NIP: [000000001002588c] PID: 7109 Comm: find Initiator: CPU Error type: UE [Load/Store] Effective address: 00007fffd2755940 Physical address: 000020181a080000 Memory failure: 0x20181a08: recovery action for dirty LRU page: Recovered Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned Memory failure: 0x20181a08: already hardware poisoned ... Watchdog CPU:38 Hard LOCKUP
After this patch we see:
Severe Machine check interrupt [Not recovered] NIP: [00007fffaae585f4] PID: 7168 Comm: find Initiator: CPU Error type: UE [Load/Store] Effective address: 00007fffaafe28ac Physical address: 00002017c0bd0000 find[7168]: unhandled signal 7 at 00007fffaae585f4 nip 00007fffaae585f4 lr 00007fffaae585e0 code 4 Memory failure: 0x2017c0bd: recovery action for dirty LRU page: Recovered
Fixes: 01eaac2b0591 ("powerpc/mce: Hookup ierror (instruction) UE errors") Fixes: ba41e1e1ccb9 ("powerpc/mce: Hookup derror (load/store) UE errors") Cc: stable@vger.kernel.org # v4.15+ Signed-off-by: Mahesh Salgaonkar mahesh@linux.vnet.ibm.com Signed-off-by: Balbir Singh bsingharora@gmail.com Reviewed-by: Balbir Singh bsingharora@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/kernel/mce_power.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)
--- a/arch/powerpc/kernel/mce_power.c +++ b/arch/powerpc/kernel/mce_power.c @@ -441,7 +441,6 @@ static int mce_handle_ierror(struct pt_r if (pfn != ULONG_MAX) { *phys_addr = (pfn << PAGE_SHIFT); - handled = 1; } } } @@ -532,9 +531,7 @@ static int mce_handle_derror(struct pt_r * kernel/exception-64s.h */ if (get_paca()->in_mce < MAX_MCE_DEPTH) - if (!mce_find_instr_ea_and_pfn(regs, addr, - phys_addr)) - handled = 1; + mce_find_instr_ea_and_pfn(regs, addr, phys_addr); } found = 1; } @@ -572,7 +569,7 @@ static long mce_handle_error(struct pt_r const struct mce_ierror_table itable[]) { struct mce_error_info mce_err = { 0 }; - uint64_t addr, phys_addr; + uint64_t addr, phys_addr = ULONG_MAX; uint64_t srr1 = regs->msr; long handled;