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| author |   Sven Schnelle <svens@linux.ibm.com> | 2020-06-17 17:30:28 +0200 |
|---|---|---|
| committer |   Heiko Carstens <heiko.carstens@de.ibm.com> | 2020-06-23 14:05:45 +0200 |
| commit | e64a1618af8566d20991607913a4d90d39b30118 (patch) | |
| tree | dd7cdc6c919f65de841690bae7ecbef49f3b96ba /arch | |
| parent | Linux 5.8-rc2 (diff) | |
| download | wireguard-linux-e64a1618af8566d20991607913a4d90d39b30118.tar.xz wireguard-linux-e64a1618af8566d20991607913a4d90d39b30118.zip | |
s390: fix system call single stepping
When single stepping an svc instruction on s390, the kernel is entered
with a PER program check interruption. The program check handler than
jumps to the system call handler by reloading the PSW. The code didn't
set GPR13 to the thread pointer in struct task_struct. This made the
kernel access invalid memory while trying to fetch the syscall function
address. Fix this by always assigned GPR13 after .Lsysc_per.
Fixes: 0b0ed657fe00 ("s390: remove critical section cleanup from entry.S")
Reported-and-tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/entry.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 496f74d98473..969b35b177dd 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -378,9 +378,9 @@ ENTRY(system_call) stmg %r8,%r15,__LC_SAVE_AREA_SYNC BPOFF lg %r12,__LC_CURRENT - lghi %r13,__TASK_thread lghi %r14,_PIF_SYSCALL .Lsysc_per: + lghi %r13,__TASK_thread lg %r15,__LC_KERNEL_STACK la %r11,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs UPDATE_VTIME %r8,%r9,__LC_SYNC_ENTER_TIMER |