This is a note to let you know that I've just added the patch titled s390/startup: avoid save_area_sync overflow to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: s390-startup-avoid-save_area_sync-overflow.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 267879df0627b9af225069376b4d0ba0712e1b4f Author: Vasily Gorbik <gor@xxxxxxxxxxxxx> Date: Thu Sep 24 19:07:04 2020 +0200 s390/startup: avoid save_area_sync overflow [ Upstream commit 2835c2ea95d50625108e47a459e1a47f6be836ce ] Currently we overflow save_area_sync and write over save_area_async. Although this is not a real problem make startup_pgm_check_handler consistent with late pgm check handler and store [%r0,%r7] directly into gpregs_save_area. Reviewed-by: Sven Schnelle <svens@xxxxxxxxxxxxx> Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/s390/boot/head.S b/arch/s390/boot/head.S index dae10961d0724..1a2c2b1ed9649 100644 --- a/arch/s390/boot/head.S +++ b/arch/s390/boot/head.S @@ -360,22 +360,23 @@ ENTRY(startup_kdump) # the save area and does disabled wait with a faulty address. # ENTRY(startup_pgm_check_handler) - stmg %r0,%r15,__LC_SAVE_AREA_SYNC - la %r1,4095 - stctg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r1) - mvc __LC_GPREGS_SAVE_AREA-4095(128,%r1),__LC_SAVE_AREA_SYNC - mvc __LC_PSW_SAVE_AREA-4095(16,%r1),__LC_PGM_OLD_PSW + stmg %r8,%r15,__LC_SAVE_AREA_SYNC + la %r8,4095 + stctg %c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r8) + stmg %r0,%r7,__LC_GPREGS_SAVE_AREA-4095(%r8) + mvc __LC_GPREGS_SAVE_AREA-4095+64(64,%r8),__LC_SAVE_AREA_SYNC + mvc __LC_PSW_SAVE_AREA-4095(16,%r8),__LC_PGM_OLD_PSW mvc __LC_RETURN_PSW(16),__LC_PGM_OLD_PSW ni __LC_RETURN_PSW,0xfc # remove IO and EX bits ni __LC_RETURN_PSW+1,0xfb # remove MCHK bit oi __LC_RETURN_PSW+1,0x2 # set wait state bit - larl %r2,.Lold_psw_disabled_wait - stg %r2,__LC_PGM_NEW_PSW+8 - l %r15,.Ldump_info_stack-.Lold_psw_disabled_wait(%r2) + larl %r9,.Lold_psw_disabled_wait + stg %r9,__LC_PGM_NEW_PSW+8 + l %r15,.Ldump_info_stack-.Lold_psw_disabled_wait(%r9) brasl %r14,print_pgm_check_info .Lold_psw_disabled_wait: - la %r1,4095 - lmg %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1) + la %r8,4095 + lmg %r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r8) lpswe __LC_RETURN_PSW # disabled wait .Ldump_info_stack: .long 0x5000 + PAGE_SIZE - STACK_FRAME_OVERHEAD