From: Heiko Carstens <hca@xxxxxxxxxxxxx> [ Upstream commit 9365965db0c7ca7fc81eee27c21d8522d7102c32 ] Clear the kernel stack backchain before potentially calling the lockdep trace_hardirqs_off/on functions. Without this walking the kernel backchain, e.g. during a panic, might stop too early. Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/s390/kernel/entry.S | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 92beb14446449..9bdf3dbd04247 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -390,6 +390,7 @@ ENTRY(system_call) mvc __PT_PSW(16,%r11),__LC_SVC_OLD_PSW mvc __PT_INT_CODE(4,%r11),__LC_SVC_ILC stg %r14,__PT_FLAGS(%r11) + xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) ENABLE_INTS .Lsysc_do_svc: # clear user controlled register to prevent speculative use @@ -406,7 +407,6 @@ ENTRY(system_call) jnl .Lsysc_nr_ok slag %r8,%r1,3 .Lsysc_nr_ok: - xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) stg %r2,__PT_ORIG_GPR2(%r11) stg %r7,STACK_FRAME_OVERHEAD(%r15) lg %r9,0(%r8,%r10) # get system call add. @@ -696,8 +696,8 @@ ENTRY(pgm_check_handler) mvc __THREAD_per_address(8,%r14),__LC_PER_ADDRESS mvc __THREAD_per_cause(2,%r14),__LC_PER_CODE mvc __THREAD_per_paid(1,%r14),__LC_PER_ACCESS_ID -6: RESTORE_SM_CLEAR_PER - xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) +6: xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) + RESTORE_SM_CLEAR_PER larl %r1,pgm_check_table llgh %r10,__PT_INT_CODE+2(%r11) nill %r10,0x007f @@ -718,8 +718,8 @@ ENTRY(pgm_check_handler) # PER event in supervisor state, must be kprobes # .Lpgm_kprobe: - RESTORE_SM_CLEAR_PER xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) + RESTORE_SM_CLEAR_PER lgr %r2,%r11 # pass pointer to pt_regs brasl %r14,do_per_trap j .Lpgm_return @@ -761,10 +761,10 @@ ENTRY(io_int_handler) stmg %r8,%r9,__PT_PSW(%r11) mvc __PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) + xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) TSTMSK __LC_CPU_FLAGS,_CIF_IGNORE_IRQ jo .Lio_restore TRACE_IRQS_OFF - xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) .Lio_loop: lgr %r2,%r11 # pass pointer to pt_regs lghi %r3,IO_INTERRUPT @@ -964,10 +964,10 @@ ENTRY(ext_int_handler) mvc __PT_INT_PARM(4,%r11),__LC_EXT_PARAMS mvc __PT_INT_PARM_LONG(8,%r11),0(%r1) xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) + xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) TSTMSK __LC_CPU_FLAGS,_CIF_IGNORE_IRQ jo .Lio_restore TRACE_IRQS_OFF - xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) lgr %r2,%r11 # pass pointer to pt_regs lghi %r3,EXT_INTERRUPT brasl %r14,do_IRQ -- 2.27.0
