From: Al Viro viro@zeniv.linux.org.uk
[ Upstream commit 50e43a57334400668952f8e551c9d87d3ed2dfef ]
We get there when sigreturn has performed obscene acts on kernel stack; in particular, the location of pt_regs has shifted. We are about to call syscall_trace(), which might stop for tracer. If that happens, we'd better have task_pt_regs() returning correct result...
Fucked-up-by: Al Viro viro@zeniv.linux.org.uk Fixes: bd6f56a75bb2 ("m68k: Missing syscall_trace() on sigreturn") Signed-off-by: Al Viro viro@zeniv.linux.org.uk Tested-by: Michael Schmitz schmitzmic@gmail.com Reviewed-by: Michael Schmitz schmitzmic@gmail.com Tested-by: Finn Thain fthain@linux-m68k.org Link: https://lore.kernel.org/r/YP2dMWeV1LkHiOpr@zeniv-ca.linux.org.uk Signed-off-by: Geert Uytterhoeven geert@linux-m68k.org Signed-off-by: Finn Thain fthain@linux-m68k.org --- arch/m68k/kernel/entry.S | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S index 417d8f0e8962..0d03b4f2077b 100644 --- a/arch/m68k/kernel/entry.S +++ b/arch/m68k/kernel/entry.S @@ -182,6 +182,8 @@ ENTRY(ret_from_signal) movel %curptr@(TASK_STACK),%a1 tstb %a1@(TINFO_FLAGS+2) jge 1f + lea %sp@(SWITCH_STACK_SIZE),%a1 + movel %a1,%curptr@(TASK_THREAD+THREAD_ESP0) jbsr syscall_trace 1: RESTORE_SWITCH_STACK addql #4,%sp