From: Al Viro <viro@zeniv.linux.org.uk>
To: linux-m68k@lists.linux-m68k.org
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Greg Ungerer <gerg@linux-m68k.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/3] m68k: update ->thread.esp0 before calling syscall_trace() in ret_from_signal
Date: Sun, 25 Jul 2021 17:19:45 +0000 [thread overview]
Message-ID: <YP2dMWeV1LkHiOpr@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <YP2c1xk9LJ0zE3KW@zeniv-ca.linux.org.uk>
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>
---
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 9dd76fbb7c6b..ff9e842cec0f 100644
--- a/arch/m68k/kernel/entry.S
+++ b/arch/m68k/kernel/entry.S
@@ -186,6 +186,8 @@ 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
--
2.11.0
next prev parent reply other threads:[~2021-07-25 17:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-25 17:18 [RFC][CFT] signal handling fixes Al Viro
2021-07-25 17:19 ` [PATCH 1/3] m68k: handle arrivals of multiple signals correctly Al Viro
2021-09-15 22:08 ` Michael Schmitz
2021-07-25 17:19 ` Al Viro [this message]
2021-09-15 22:19 ` [PATCH 2/3] m68k: update ->thread.esp0 before calling syscall_trace() in ret_from_signal Michael Schmitz
2021-07-25 17:20 ` [PATCH 3/3] m68k: leave stack mangling to asm wrapper of sigreturn() Al Viro
2021-09-15 23:35 ` Michael Schmitz
2021-09-16 0:19 ` Al Viro
2021-09-16 0:53 ` Michael Schmitz
2021-09-16 3:21 ` Al Viro
2021-09-16 5:02 ` Michael Schmitz
2021-09-16 16:14 ` Al Viro
2021-07-27 10:21 ` [RFC][CFT] signal handling fixes Finn Thain
2021-07-27 14:42 ` Al Viro
2021-07-28 1:23 ` Finn Thain
2021-08-11 1:42 ` Finn Thain
2021-09-16 9:03 ` Finn Thain
2021-09-23 14:43 ` Geert Uytterhoeven
2021-09-23 14:45 ` Geert Uytterhoeven
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