| Message ID | 20171223164923.10587-2-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 4552d128c26e0f0f27a5bd2fadc24092b8f6c1d7 |
| Headers | show |
| Series | sreset driven panic/oops message printing fixes | expand |
On Sun, Dec 24, 2017 at 02:49:22AM +1000, Nicholas Piggin wrote: > 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> > --- > arch/powerpc/kernel/traps.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c > index f3eb61be0d30..109989676776 100644 > --- a/arch/powerpc/kernel/traps.c > +++ b/arch/powerpc/kernel/traps.c > @@ -337,7 +337,7 @@ void system_reset_exception(struct pt_regs *regs) > * 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);
On Sat, 2017-12-23 at 16:49:22 UTC, Nicholas Piggin wrote: > 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> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/4552d128c26e0f0f27a5bd2fadc240 cheers
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index f3eb61be0d30..109989676776 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -337,7 +337,7 @@ void system_reset_exception(struct pt_regs *regs) * 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);
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> --- arch/powerpc/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)