Messages in this thread | | | From | "Luck, Tony" <> | Date | Wed, 7 Sep 2011 22:16:04 -0700 | Subject | RE: [PATCH 5/5] mce: recover from "action required" errors reported in data path in usermode |
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> __memory_failure() handling calls some routines, such > as is_free_buddy_page(), which needs to acquire the spin > lock, zone->lock. How can we guarantee that other CPUs > haven't acquired the lock when receiving #mc broadcast > and entering #mc handlers ?
By the time I call __memory_failure() - the other cpus have been released from mce handler - so they are back executing normal code.
But Chen Gong's earlier comments made me look again at entry_64.S code - ane I realized that I missed seeing code in the return path from do_machine_check() that switched from MCE stack to regular kernel stack before processing TIF_MCE_NOTIFY.
I may go back and re-visit a path that I looked at to change do_machine_check from "void" return to "unsigned long" and have it return the address for the "AR" case and "0" otherwise. Then we could switch out of machine check stack to non-mce context to call __memory_failure(). When I looked at this before the entry_64.S path looked plausible. The 32-bit path looked to be painful (too many macros in entry_32.S)
-Tony
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