6c1e0256fa
On exception exit, we restore the previous context tracking state based on the regs of the interrupted frame. Iff that frame is in user mode as stated by user_mode() helper, we restore the context tracking user mode. However there is a tiny chunck of low level arch code after we pass through user_enter() and until the CPU eventually resumes userspace. If an exception happens in this tiny area, exception_enter() correctly exits the context tracking user mode but exception_exit() won't restore it because of the value returned by user_mode(regs). As a result we may return to userspace with the wrong context tracking state. To fix this, change exception_enter() to return the context tracking state prior to its call and pass this saved state to exception_exit(). This restores the real context tracking state of the interrupted frame. (May be this patch was suggested to me, I don't recall exactly. If so, sorry for the missing credit). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Mats Liljegren <mats.liljegren@enea.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
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| boot | ||
| configs | ||
| crypto | ||
| ia32 | ||
| include | ||
| kernel | ||
| kvm | ||
| lguest | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
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| platform | ||
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| realmode | ||
| syscalls | ||
| tools | ||
| um | ||
| vdso | ||
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| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile.um | ||
| Makefile_32.cpu | ||