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Masami Hiramatsu
69af7e23a6
Since get_kprobe_ctlblk() uses smp_processor_id() to access
per-cpu variable, it hits smp_processor_id sanity check as below.
[ 7.006928] BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
[ 7.007859] caller is debug_smp_processor_id+0x20/0x24
[ 7.008438] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.16.0-rc1-00192-g4eb17253e4b5 #1
[ 7.008890] Hardware name: Generic DT based system
[ 7.009917] [<c0313f0c>] (unwind_backtrace) from [<c030e6d8>] (show_stack+0x20/0x24)
[ 7.010473] [<c030e6d8>] (show_stack) from [<c0c64694>] (dump_stack+0x84/0x98)
[ 7.010990] [<c0c64694>] (dump_stack) from [<c071ca5c>] (check_preemption_disabled+0x138/0x13c)
[ 7.011592] [<c071ca5c>] (check_preemption_disabled) from [<c071ca80>] (debug_smp_processor_id+0x20/0x24)
[ 7.012214] [<c071ca80>] (debug_smp_processor_id) from [<c03335e0>] (optimized_callback+0x2c/0xe4)
[ 7.013077] [<c03335e0>] (optimized_callback) from [<bf0021b0>] (0xbf0021b0)
To fix this issue, call get_kprobe_ctlblk() right after
irq-disabled since that disables preemption.
Fixes: 0dc016dbd8 ("ARM: kprobes: enable OPTPROBES for ARM 32")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
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In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.