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| Started by | Andy Lutomirski <luto@amacapital.net> |
|---|---|
| First post | 2015-08-15 00:40 +0200 |
| Last post | 2015-08-15 19:00 +0200 |
| Articles | 2 — 2 participants |
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More hw_breakpoint scariness reduction Andy Lutomirski <luto@amacapital.net> - 2015-08-15 00:40 +0200
Re: More hw_breakpoint scariness reduction Frederic Weisbecker <fweisbec@gmail.com> - 2015-08-15 19:00 +0200
| From | Andy Lutomirski <luto@amacapital.net> |
|---|---|
| Date | 2015-08-15 00:40 +0200 |
| Subject | More hw_breakpoint scariness reduction |
| Message-ID | <pXvNM-7b2-15@gated-at.bofh.it> |
Would you all consider it acceptable to disallow watchpoints on per cpu data entirely? I can think of a *lot* of places where hitting #DB when accessing per cpu data from entry asm would be bad. Of course, actually implementing that might be less than entirely fun, given that a cpu could be onlined after creating a watchpoint. --Andy -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Frederic Weisbecker <fweisbec@gmail.com> |
|---|---|
| Date | 2015-08-15 19:00 +0200 |
| Message-ID | <pXMYj-7jF-19@gated-at.bofh.it> |
| In reply to | #1207930 |
2015-08-15 0:38 GMT+02:00 Andy Lutomirski <luto@amacapital.net>: > Would you all consider it acceptable to disallow watchpoints on per > cpu data entirely? I can think of a *lot* of places where hitting #DB > when accessing per cpu data from entry asm would be bad. > > Of course, actually implementing that might be less than entirely fun, > given that a cpu could be onlined after creating a watchpoint. Well I think there will always be places where setting a breakpoint is a bad idea. The same goes for kprobes. We can't fix all of them. Kernel breakpoints can only be set by root users so it's not a security issue. Besides, kernel breakpoints should only be used by kernel hackers (perf, kdb). Given the wide use of per-cpu data, forbidding all of them will seriously reduce the usability of kernel breakpoints. Not that I think they are really used in practice though ;-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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