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| author | Thomas Gleixner <tglx@linutronix.de> | 2018-01-03 21:52:04 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-04 01:19:32 +0300 |
| commit | d7732ba55c4b6a2da339bb12589c515830cfac2c (patch) | |
| tree | cdf1579e8d02d42c408b607c4a7583038004f2a4 /Kbuild | |
| parent | 3ffdeb1a02be3086f1411a15c5b9c481fa28e21f (diff) | |
| download | linux-d7732ba55c4b6a2da339bb12589c515830cfac2c.tar.xz | |
x86/pti: Switch to kernel CR3 at early in entry_SYSCALL_compat()
The preparation for PTI which added CR3 switching to the entry code
misplaced the CR3 switch in entry_SYSCALL_compat().
With PTI enabled the entry code tries to access a per cpu variable after
switching to kernel GS. This fails because that variable is not mapped to
user space. This results in a double fault and in the worst case a kernel
crash.
Move the switch ahead of the access and clobber RSP which has been saved
already.
Fixes: 8a09317b895f ("x86/mm/pti: Prepare the x86/entry assembly code for entry/exit CR3 switching")
Reported-by: Lars Wendler <wendler.lars@web.de>
Reported-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>,
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Cc: Peter Zijlstra <peterz@infradead.org>,
Cc: Greg KH <gregkh@linuxfoundation.org>, ,
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Cc: Juergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801031949200.1957@nanos
Diffstat (limited to 'Kbuild')
0 files changed, 0 insertions, 0 deletions