5.15-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens hca@linux.ibm.com
commit ae952eea6f4a7e2193f8721a5366049946e012e7 upstream.
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: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/kernel/entry.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -676,7 +676,7 @@ ENTRY(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 + mvc __PT_ORIG_GPR2(8,%r11),__LC_LAST_BREAK xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) lgr %r2,%r11 # pass pointer to pt_regs jg kernel_stack_overflow