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| author | Lai Jiangshan <laijs@linux.alibaba.com> | 2021-02-04 23:27:07 +0800 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2021-02-05 20:13:12 +0100 |
| commit | 3943abf2dbfae9ea4d2da05c1db569a0603f76da (patch) | |
| tree | 36182b39ffc8b5ad40e4985c999665c8b5e26956 /arch/m68k/kernel | |
| parent | c4bed4b96918ff1d062ee81fdae4d207da4fa9b0 (diff) | |
| download | linux-3943abf2dbfae9ea4d2da05c1db569a0603f76da.tar.bz2 | |
x86/debug: Prevent data breakpoints on cpu_dr7
local_db_save() is called at the start of exc_debug_kernel(), reads DR7 and
disables breakpoints to prevent recursion.
When running in a guest (X86_FEATURE_HYPERVISOR), local_db_save() reads the
per-cpu variable cpu_dr7 to check whether a breakpoint is active or not
before it accesses DR7.
A data breakpoint on cpu_dr7 therefore results in infinite #DB recursion.
Disallow data breakpoints on cpu_dr7 to prevent that.
Fixes: 84b6a3491567a("x86/entry: Optimize local_db_save() for virt")
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210204152708.21308-2-jiangshanlai@gmail.com
Diffstat (limited to 'arch/m68k/kernel')
0 files changed, 0 insertions, 0 deletions