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author | Tomislav Novak <tnovak@meta.com> | 2023-06-05 22:19:23 +0300 |
---|---|---|
committer | Will Deacon <will@kernel.org> | 2023-08-18 19:04:09 +0300 |
commit | d11a69873d9a7435fe6a48531e165ab80a8b1221 (patch) | |
tree | 496449640d13575a9a703f6161042ac9990b5a61 /arch/arm64/kernel | |
parent | f4e2bd91ddf5e8543cbe7ad80b3fba3d2dc63fa3 (diff) | |
download | linux-d11a69873d9a7435fe6a48531e165ab80a8b1221.tar.xz |
hw_breakpoint: fix single-stepping when using bpf_overflow_handler
Arm platforms use is_default_overflow_handler() to determine if the
hw_breakpoint code should single-step over the breakpoint trigger or
let the custom handler deal with it.
Since bpf_overflow_handler() currently isn't recognized as a default
handler, attaching a BPF program to a PERF_TYPE_BREAKPOINT event causes
it to keep firing (the instruction triggering the data abort exception
is never skipped). For example:
# bpftrace -e 'watchpoint:0x10000:4:w { print("hit") }' -c ./test
Attaching 1 probe...
hit
hit
[...]
^C
(./test performs a single 4-byte store to 0x10000)
This patch replaces the check with uses_default_overflow_handler(),
which accounts for the bpf_overflow_handler() case by also testing
if one of the perf_event_output functions gets invoked indirectly,
via orig_default_handler.
Signed-off-by: Tomislav Novak <tnovak@meta.com>
Tested-by: Samuel Gosselin <sgosselin@google.com> # arm64
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/linux-arm-kernel/20220923203644.2731604-1-tnovak@fb.com/
Link: https://lore.kernel.org/r/20230605191923.1219974-1-tnovak@meta.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r-- | arch/arm64/kernel/hw_breakpoint.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index db2a1861bb97..35225632d70a 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -654,7 +654,7 @@ static int breakpoint_handler(unsigned long unused, unsigned long esr, perf_bp_event(bp, regs); /* Do we need to handle the stepping? */ - if (is_default_overflow_handler(bp)) + if (uses_default_overflow_handler(bp)) step = 1; unlock: rcu_read_unlock(); @@ -733,7 +733,7 @@ static u64 get_distance_from_watchpoint(unsigned long addr, u64 val, static int watchpoint_report(struct perf_event *wp, unsigned long addr, struct pt_regs *regs) { - int step = is_default_overflow_handler(wp); + int step = uses_default_overflow_handler(wp); struct arch_hw_breakpoint *info = counter_arch_bp(wp); info->trigger = addr; |