From: huawei.libin@huawei.com (Li Bin)
To: linux-arm-kernel@lists.infradead.org
Subject: [BUG] arm64/hw_breakpoint: trigger breakpoint exception infinitely
Date: Tue, 26 Apr 2016 16:23:19 +0800 [thread overview]
Message-ID: <571F2577.2080203@huawei.com> (raw)
This bug can be reproduced by compiling the hw_breakpoint sample
module that is in the kernel tree, when loading it with parameter
ksym=nfsdstats, and running nfsstat:
$ insmod data_breakpoint.ko ksym=nfsdstats
$ nfsstat
It will trigger breakpoint exception infinitely:
nfsdstats value is changed
...
Call trace:
...
Dump stack from sample_hbp_handler
nfsdstats value is changed
...
Call trace:
...
Dump stack from sample_hbp_handler
......
......
This is because that the overflow_handler is set to the callback
in the module, and in watchpoint_handler, it will not disable the
breakpoint (and set single step that reenable it), so when exception
return, it will trigger the breakpoint exception again immediately...
Li Bin
next reply other threads:[~2016-04-26 8:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-26 8:23 Li Bin [this message]
2016-04-26 12:22 ` [BUG] arm64/hw_breakpoint: trigger breakpoint exception infinitely Will Deacon
2016-04-27 2:35 ` Li Bin
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