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m68k: Update ->thread.esp0 before calling syscall_trace() in ret_from_signal

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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>
This commit is contained in:
Al Viro 2021-07-25 17:19:45 +00:00 committed by Geert Uytterhoeven
parent 4bb0bd81ce
commit 50e43a5733
1 changed files with 2 additions and 0 deletions
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2
arch/m68k/kernel/entry.S
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@ -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