path: root/tools
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authorMichael Neuling <mikey@neuling.org>2018-09-24 17:27:04 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2018-09-25 22:51:08 +1000
commitcf13435b730a502e814c63c84d93db131e563f5f (patch)
tree46d7d088182d0ca86b7f5b7b45ecbf5dfa82e66f /tools
parentpowerpc/pseries: Fix unitialized timer reset on migration (diff)
powerpc/tm: Fix userspace r13 corruption
When we treclaim we store the userspace checkpointed r13 to a scratch SPR and then later save the scratch SPR to the user thread struct. Unfortunately, this doesn't work as accessing the user thread struct can take an SLB fault and the SLB fault handler will write the same scratch SPRG that now contains the userspace r13. To fix this, we store r13 to the kernel stack (which can't fault) before we access the user thread struct. Found by running P8 guest + powervm + disable_1tb_segments + TM. Seen as a random userspace segfault with r13 looking like a kernel address. Signed-off-by: Michael Neuling <mikey@neuling.org> Reviewed-by: Breno Leitao <leitao@debian.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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