| Message ID | 20230801011744.153973-1-bgray@linux.ibm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Rework perf and ptrace watchpoint tracking | expand |
Le 01/08/2023 à 03:17, Benjamin Gray a écrit : > Syzkaller triggered a null pointer dereference in the > arch_unregister_hw_breakpoint() hook. This is due to accessing > the bp->ctx->task field changing to -1 while we iterate the breakpoints. > > This series refactors the breakpoint tracking logic to remove the > dependency on bp->ctx entirely. It also simplifies handling of ptrace and > perf breakpoints, making insertion less restrictive. Is there any link between this series and the following issue: https://github.com/linuxppc/issues/issues/38 Christophe > > If merged, it allows several arch hooks that PowerPC was the sole user of > to be removed. > > Benjamin Gray (7): > powerpc/watchpoints: Explain thread_change_pc() more > powerpc/watchpoints: Don't track info persistently > powerpc/watchpoints: Track perf single step directly on the breakpoint > powerpc/watchpoints: Simplify watchpoint reinsertion > powerpc/watchpoints: Remove ptrace/perf exclusion tracking > selftests/powerpc/ptrace: Update ptrace-perf watchpoint selftest > perf/hw_breakpoint: Remove arch breakpoint hooks > > arch/powerpc/include/asm/hw_breakpoint.h | 1 + > arch/powerpc/include/asm/processor.h | 5 - > arch/powerpc/kernel/hw_breakpoint.c | 388 +----- > include/linux/hw_breakpoint.h | 3 - > kernel/events/hw_breakpoint.c | 28 - > .../testing/selftests/powerpc/ptrace/Makefile | 1 + > .../powerpc/ptrace/ptrace-perf-asm.S | 33 + > .../powerpc/ptrace/ptrace-perf-hwbreak.c | 1104 +++++++---------- > 8 files changed, 537 insertions(+), 1026 deletions(-) > create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace-perf-asm.S > rewrite tools/testing/selftests/powerpc/ptrace/ptrace-perf-hwbreak.c (93%) >
Christophe Leroy <christophe.leroy@csgroup.eu> writes: > Le 01/08/2023 à 03:17, Benjamin Gray a écrit : >> Syzkaller triggered a null pointer dereference in the >> arch_unregister_hw_breakpoint() hook. This is due to accessing >> the bp->ctx->task field changing to -1 while we iterate the breakpoints. >> >> This series refactors the breakpoint tracking logic to remove the >> dependency on bp->ctx entirely. It also simplifies handling of ptrace and >> perf breakpoints, making insertion less restrictive. > > Is there any link between this series and the following issue: > https://github.com/linuxppc/issues/issues/38 AFAIK no, Ben started looking at the breakpoint code due to a syzkaller report of an oops. But this series would resolve that issue AFAICS, so I guess they are linked in that sense. cheers
On Tue, 01 Aug 2023 11:17:37 +1000, Benjamin Gray wrote: > Syzkaller triggered a null pointer dereference in the > arch_unregister_hw_breakpoint() hook. This is due to accessing > the bp->ctx->task field changing to -1 while we iterate the breakpoints. > > This series refactors the breakpoint tracking logic to remove the > dependency on bp->ctx entirely. It also simplifies handling of ptrace and > perf breakpoints, making insertion less restrictive. > > [...] Applied to powerpc/next. [1/7] powerpc/watchpoints: Explain thread_change_pc() more https://git.kernel.org/powerpc/c/8f8f1cd67aa026c9dab8eb4e087e4a2d8fa9d5bc [2/7] powerpc/watchpoints: Don't track info persistently https://git.kernel.org/powerpc/c/668a6ec6ed57f0248070c490aba75a9572e4b0a4 [3/7] powerpc/watchpoints: Track perf single step directly on the breakpoint https://git.kernel.org/powerpc/c/1e60f3564bad09962646bf8c2af588ecf518d337 [4/7] powerpc/watchpoints: Simplify watchpoint reinsertion https://git.kernel.org/powerpc/c/5a2d8b9c06712b52b2f0f2fc9a144242277fda74 [5/7] powerpc/watchpoints: Remove ptrace/perf exclusion tracking https://git.kernel.org/powerpc/c/bd29813ae10698f7bdfb3c68eacbb6464ec701ff [6/7] selftests/powerpc/ptrace: Update ptrace-perf watchpoint selftest https://git.kernel.org/powerpc/c/58709f6fc327a997daeeca77aa5e6bd4d4c238cf [7/7] perf/hw_breakpoint: Remove arch breakpoint hooks https://git.kernel.org/powerpc/c/53834a0c09252dea7918a9e1788bad880690900b cheers