powerpc/eeh: Avoid use after free in eeh_handle_special_event()

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commit daeba2956f upstream.

eeh_handle_special_event() is called when an EEH event is detected but
can't be narrowed down to a specific PE.  This function looks through
every PE to find one in an erroneous state, then calls the regular event
handler eeh_handle_normal_event() once it knows which PE has an error.

However, if eeh_handle_normal_event() found that the PE cannot possibly
be recovered, it will free it, rendering the passed PE stale.
This leads to a use after free in eeh_handle_special_event() as it attempts to
clear the "recovering" state on the PE after eeh_handle_normal_event() returns.

Thus, make sure the PE is valid when attempting to clear state in
eeh_handle_special_event().

Fixes: 8a6b1bc70d ("powerpc/eeh: EEH core to handle special event")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Russell Currey 2017-04-19 17:39:26 +10:00 • committed by Greg Kroah-Hartman

parent 690f09eb52

commit 222f1d668d

1 changed files with 15 additions and 4 deletions

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arch/powerpc/kernel/eeh_driver.c

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