From: Dmitry Vyukov <dvyukov@google.com> To: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>, LKML <linux-kernel@vger.kernel.org>, Catalin Marinas <catalin.marinas@arm.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Mark Rutland <mark.rutland@arm.com> Cc: syzkaller <syzkaller@googlegroups.com> Subject: Does LOCKDEP work on ARM64? Date: Sat, 24 Oct 2020 11:51:49 +0200 [thread overview] Message-ID: <CACT4Y+aAzoJ48Mh1wNYD17pJqyEcDnrxGfApir=-j171TnQXhw@mail.gmail.com> (raw) Hello ARM64/LOCKDEP maintainers, I've started experimenting with running syzkaller on ARM64 using QEMU/TCG. Total execution speed is very low and it ran just a handful of tests, but I am seeing massive amounts of locking bugs. Most of these were not observed on x86_64, while x86_64 ran gazillions of tests by now and most of these are trivial to trigger (depend only on call stack) and they do not look ARM64-specific. So I wonder: 1. Are there any known issues with LOCKDEP on ARM64? 2. Or are all these real and it's x86_64 LOCKDEP that's misbehaving? 3. Or are both x86_64 and ARM64 fine and these are just somehow ARM64-specific? Here are details. Kernel is on f9893351acaecf0a414baf9942b48d5bb5c688c6 (recent upstream HEAD). Kernel config: https://gist.githubusercontent.com/dvyukov/c92a1e08f3f7e22b1f0387096d98b18b/raw/9f79f83c3b018ac27a040649f7d0fef36b63b960/gistfile1.txt Here is one "Invalid wait context". It looks like just a put_user inside of syscall function: https://gist.githubusercontent.com/dvyukov/15639a949278a981c8eb125b3088a6b8/raw/286117bc292578c07c8afbf0fa563cd5528821e7/gistfile1.txt Here is one "bad unlock balance detected". The looks well balanced and the code path is well exercised: https://gist.githubusercontent.com/dvyukov/805f867823b9f77a26c2ebedec5b9b9e/raw/2e6605fb5c90f56ebd1ccda78d613b5c219dfb82/gistfile1.txt Here is one "workqueue leaked lock". Again, lock/unlock are very local and there is no control flow in between: https://gist.githubusercontent.com/dvyukov/4d18d35a79d7e74bf66d6e7ec3794ec0/raw/1ff3e2a5d3a825eb0d196af1f81c67a47fa3a2f6/gistfile1.txt Here is one confusing "bad unlock balance detected": https://gist.githubusercontent.com/dvyukov/e222fa34e04104678c52a5b5b1ad15a3/raw/943c6ebbc022418b89fa63b6282fa1f1f40a276a/gistfile1.txt Here is one confusing "suspicious RCU usage": https://gist.githubusercontent.com/dvyukov/77b0ec246e1db86e549a80e4a11ec218/raw/0bce97be186c0a6617d8835a694443ed1aa2a98a/gistfile1.txt Overall I have more than 50 of these now.
WARNING: multiple messages have this Message-ID (diff)
From: Dmitry Vyukov <dvyukov@google.com> To: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>, LKML <linux-kernel@vger.kernel.org>, Catalin Marinas <catalin.marinas@arm.com>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Mark Rutland <mark.rutland@arm.com> Cc: syzkaller <syzkaller@googlegroups.com> Subject: Does LOCKDEP work on ARM64? Date: Sat, 24 Oct 2020 11:51:49 +0200 [thread overview] Message-ID: <CACT4Y+aAzoJ48Mh1wNYD17pJqyEcDnrxGfApir=-j171TnQXhw@mail.gmail.com> (raw) Hello ARM64/LOCKDEP maintainers, I've started experimenting with running syzkaller on ARM64 using QEMU/TCG. Total execution speed is very low and it ran just a handful of tests, but I am seeing massive amounts of locking bugs. Most of these were not observed on x86_64, while x86_64 ran gazillions of tests by now and most of these are trivial to trigger (depend only on call stack) and they do not look ARM64-specific. So I wonder: 1. Are there any known issues with LOCKDEP on ARM64? 2. Or are all these real and it's x86_64 LOCKDEP that's misbehaving? 3. Or are both x86_64 and ARM64 fine and these are just somehow ARM64-specific? Here are details. Kernel is on f9893351acaecf0a414baf9942b48d5bb5c688c6 (recent upstream HEAD). Kernel config: https://gist.githubusercontent.com/dvyukov/c92a1e08f3f7e22b1f0387096d98b18b/raw/9f79f83c3b018ac27a040649f7d0fef36b63b960/gistfile1.txt Here is one "Invalid wait context". It looks like just a put_user inside of syscall function: https://gist.githubusercontent.com/dvyukov/15639a949278a981c8eb125b3088a6b8/raw/286117bc292578c07c8afbf0fa563cd5528821e7/gistfile1.txt Here is one "bad unlock balance detected". The looks well balanced and the code path is well exercised: https://gist.githubusercontent.com/dvyukov/805f867823b9f77a26c2ebedec5b9b9e/raw/2e6605fb5c90f56ebd1ccda78d613b5c219dfb82/gistfile1.txt Here is one "workqueue leaked lock". Again, lock/unlock are very local and there is no control flow in between: https://gist.githubusercontent.com/dvyukov/4d18d35a79d7e74bf66d6e7ec3794ec0/raw/1ff3e2a5d3a825eb0d196af1f81c67a47fa3a2f6/gistfile1.txt Here is one confusing "bad unlock balance detected": https://gist.githubusercontent.com/dvyukov/e222fa34e04104678c52a5b5b1ad15a3/raw/943c6ebbc022418b89fa63b6282fa1f1f40a276a/gistfile1.txt Here is one confusing "suspicious RCU usage": https://gist.githubusercontent.com/dvyukov/77b0ec246e1db86e549a80e4a11ec218/raw/0bce97be186c0a6617d8835a694443ed1aa2a98a/gistfile1.txt Overall I have more than 50 of these now. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2020-10-24 9:52 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-10-24 9:51 Dmitry Vyukov [this message] 2020-10-24 9:51 ` Does LOCKDEP work on ARM64? Dmitry Vyukov 2020-10-28 17:56 ` Will Deacon 2020-10-28 17:56 ` Will Deacon 2020-11-03 17:11 ` Mark Rutland 2020-11-03 17:11 ` Mark Rutland
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