[PATCH 0/7] Rework perf and ptrace watchpoint tracking

[Christophe Leroy]

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%)
>