diff options
| author | Karol Herbst <kherbst@redhat.com> | 2017-11-27 08:51:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-12-11 15:35:18 +0100 |
| commit | 6d60ce384d1d5ca32b595244db4077a419acc687 (patch) | |
| tree | 3a7947b4194a2bdcb74eb37a7258bde3a69d19ba /arch/x86/mm/ioremap.c | |
| parent | 6d7e0ba2d2be9e50cccba213baf07e0e183c1b24 (diff) | |
x86/mm/kmmio: Fix mmiotrace for page unaligned addresses
If something calls ioremap() with an address not aligned to PAGE_SIZE, the
returned address might be not aligned as well. This led to a probe
registered on exactly the returned address, but the entire page was armed
for mmiotracing.
On calling iounmap() the address passed to unregister_kmmio_probe() was
PAGE_SIZE aligned by the caller leading to a complete freeze of the
machine.
We should always page align addresses while (un)registerung mappings,
because the mmiotracer works on top of pages, not mappings. We still keep
track of the probes based on their real addresses and lengths though,
because the mmiotrace still needs to know what are mapped memory regions.
Also move the call to mmiotrace_iounmap() prior page aligning the address,
so that all probes are unregistered properly, otherwise the kernel ends up
failing memory allocations randomly after disabling the mmiotracer.
Tested-by: Lyude <lyude@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Acked-by: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: nouveau@lists.freedesktop.org
Link: http://lkml.kernel.org/r/20171127075139.4928-1-kherbst@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/ioremap.c')
| -rw-r--r-- | arch/x86/mm/ioremap.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 6e4573b1da34..c45b6ec5357b 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -404,11 +404,11 @@ void iounmap(volatile void __iomem *addr) return; } + mmiotrace_iounmap(addr); + addr = (volatile void __iomem *) (PAGE_MASK & (unsigned long __force)addr); - mmiotrace_iounmap(addr); - /* Use the vm area unlocked, assuming the caller ensures there isn't another iounmap for the same address in parallel. Reuse of the virtual address is prevented by |