4.14-stable review patch. If anyone has any objections, please let me know.
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From: Nicholas Piggin npiggin@gmail.com
[ Upstream commit 4552d128c26e0f0f27a5bd2fadc24092b8f6c1d7 ]
The die() oops path contains a serializing lock to prevent oops messages from being interleaved. In the case of a system reset initiated oops (e.g., qemu nmi command), __die was being called which lacks that synchronisation and oops reports could be interleaved across CPUs.
A recent patch 4388c9b3a6ee7 ("powerpc: Do not send system reset request through the oops path") changed this to __die to avoid the debugger() call, but there is no real harm to calling it twice if the first time fell through. So go back to using die() here. This was observed to fix the problem.
Fixes: 4388c9b3a6ee7 ("powerpc: Do not send system reset request through the oops path") Signed-off-by: Nicholas Piggin npiggin@gmail.com Reviewed-by: David Gibson david@gibson.dropbear.id.au Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -336,7 +336,7 @@ void system_reset_exception(struct pt_re * No debugger or crash dump registered, print logs then * panic. */ - __die("System Reset", regs, SIGABRT); + die("System Reset", regs, SIGABRT);
mdelay(2*MSEC_PER_SEC); /* Wait a little while for others to print */ add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);