Linux kernel for uConsole
bd14406b78
We need to change the breakpoint even if the attr with new fields has
disabled set to true.
Current code prevents following user code to change the breakpoint
address:
ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[0]), addr_1)
ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[0]), addr_2)
ptrace(PTRACE_POKEUSER, child, offsetof(struct user, u_debugreg[7]), dr7)
The first PTRACE_POKEUSER creates the breakpoint with attr.disabled set
to true:
ptrace_set_breakpoint_addr(nr = 0)
struct perf_event *bp = t->ptrace_bps[nr];
ptrace_register_breakpoint(..., disabled = true)
ptrace_fill_bp_fields(..., disabled)
register_user_hw_breakpoint
So the second PTRACE_POKEUSER will be omitted:
ptrace_set_breakpoint_addr(nr = 0)
struct perf_event *bp = t->ptrace_bps[nr];
struct perf_event_attr attr = bp->attr;
modify_user_hw_breakpoint(bp, &attr)
if (!attr->disabled)
modify_user_hw_breakpoint_check
Reported-by: Milind Chabbi <chabbi.milind@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180827091228.2878-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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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
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
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.