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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-02-03 17:37:15 +0100 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2014-05-19 07:54:37 +0200 |
| commit | 0e37e30a8f55140dc1702b2d2008d41155bb3360 (patch) | |
| tree | 5c4007ca42b6df8ce823afa7289568fa692ff1de | |
| parent | efe55430442061cb01177c88b891a678935a6eae (diff) | |
| download | linux-stable-0e37e30a8f55140dc1702b2d2008d41155bb3360.tar.gz linux-stable-0e37e30a8f55140dc1702b2d2008d41155bb3360.tar.bz2 linux-stable-0e37e30a8f55140dc1702b2d2008d41155bb3360.zip | |
s390: fix kernel crash due to linkage stack instructions
commit 8d7f6690cedb83456edd41c9bd583783f0703bf0 upstream
The kernel currently crashes with a low-address-protection exception
if a user space process executes an instruction that tries to use the
linkage stack. Set the base-ASTE origin and the subspace-ASTE origin
of the dispatchable-unit-control-table to point to a dummy ASTE.
Set up control register 15 to point to an empty linkage stack with no
room left.
A user space process with a linkage stack instruction will still crash
but with a different exception which is correctly translated to a
segmentation fault instead of a kernel oops.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[dannf: backported to Debian's 2.6.32]
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -rw-r--r-- | arch/s390/kernel/head64.S | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S index d984a2a380c3..5b27ed023392 100644 --- a/arch/s390/kernel/head64.S +++ b/arch/s390/kernel/head64.S @@ -124,7 +124,7 @@ startup_continue: .quad 0 # cr12: tracing off .quad 0 # cr13: home space segment table .quad 0xc0000000 # cr14: machine check handling off - .quad 0 # cr15: linkage stack operations + .quad .Llinkage_stack # cr15: linkage stack operations .Lpcmsk:.quad 0x0000000180000000 .L4malign:.quad 0xffffffffffc00000 .Lscan2g:.quad 0x80000000 + 0x20000 - 8 # 2GB + 128K - 8 @@ -139,12 +139,15 @@ startup_continue: .Lparmaddr: .quad PARMAREA .align 64 -.Lduct: .long 0,0,0,0,.Lduald,0,0,0 +.Lduct: .long 0,.Laste,.Laste,0,.Lduald,0,0,0 .long 0,0,0,0,0,0,0,0 +.Laste: .quad 0,0xffffffffffffffff,0,0,0,0,0,0 .align 128 .Lduald:.rept 8 .long 0x80000000,0,0,0 # invalid access-list entries .endr +.Llinkage_stack: + .long 0,0,0x89000000,0,0,0,0x8a000000,0 .org 0x12000 .globl _ehead |