6.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Heiko Carstens hca@linux.ibm.com
[ Upstream commit ae952eea6f4a7e2193f8721a5366049946e012e7 ]
In case of stack corruption stack_invalid() is called and the expectation is that register r10 contains the last breaking event address. This dependency is quite subtle and broke a couple of years ago without that anybody noticed.
Fix this by getting rid of the dependency and read the last breaking event address from lowcore.
Fixes: 56e62a737028 ("s390: convert to generic entry") Acked-by: Ilya Leoshkevich iii@linux.ibm.com Reviewed-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/kernel/entry.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 88e09a650d2df..ce8bac77cbc1b 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -601,7 +601,8 @@ SYM_CODE_START(stack_overflow) stmg %r0,%r7,__PT_R0(%r11) stmg %r8,%r9,__PT_PSW(%r11) mvc __PT_R8(64,%r11),0(%r14) - stg %r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2 + GET_LC %r2 + mvc __PT_ORIG_GPR2(8,%r11),__LC_PGM_LAST_BREAK(%r2) xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) lgr %r2,%r11 # pass pointer to pt_regs jg kernel_stack_overflow