From 2b97956af60810cd382b86b9ce9aea421b889861 Mon Sep 17 00:00:00 2001 From: Nuoqi Gui Date: Fri, 4 Sep 2026 12:41:55 +0200 Subject: selftests/bpf: Test rhtab kptr cancellation semantics Resizable hash-map updates and deletions must not perform full special-field destruction in their caller context. In particular, a referenced kptr must remain attached to the allocation until the memory allocator destructor can release it safely. Add separate coverage for both affected paths. The update test stores a task kptr, replaces the ordinary value bytes with BPF_EXIST, and verifies that the kptr survived. The delete test removes an element and exchanges its kptr through the still-valid map-value pointer before the allocation is reclaimed. Both cases observe a NULL kptr when rhtab uses bpf_obj_free_fields(). They recover and release the reference after rhtab switches to cancellation semantics. Signed-off-by: Nuoqi Gui [ kkd: Split update and delete coverage and rewrote the commit log ] Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904104203.345917-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- lib/trace_readwrite.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 lib/trace_readwrite.c (limited to 'lib/trace_readwrite.c') diff --git a/lib/trace_readwrite.c b/lib/trace_readwrite.c new file mode 100644 index 000000000..a94cd56a1 --- /dev/null +++ b/lib/trace_readwrite.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Register read and write tracepoints + * + * Copyright (c) 2021-2022 Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#include +#include +#include + +#define CREATE_TRACE_POINTS +#include + +#ifdef CONFIG_TRACE_MMIO_ACCESS +void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr, + unsigned long caller_addr, unsigned long caller_addr0) +{ + trace_rwmmio_write(caller_addr, caller_addr0, val, width, addr); +} +EXPORT_SYMBOL_GPL(log_write_mmio); +EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_write); + +void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr, + unsigned long caller_addr, unsigned long caller_addr0) +{ + trace_rwmmio_post_write(caller_addr, caller_addr0, val, width, addr); +} +EXPORT_SYMBOL_GPL(log_post_write_mmio); +EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_post_write); + +void log_read_mmio(u8 width, const volatile void __iomem *addr, + unsigned long caller_addr, unsigned long caller_addr0) +{ + trace_rwmmio_read(caller_addr, caller_addr0, width, addr); +} +EXPORT_SYMBOL_GPL(log_read_mmio); +EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_read); + +void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr, + unsigned long caller_addr, unsigned long caller_addr0) +{ + trace_rwmmio_post_read(caller_addr, caller_addr0, val, width, addr); +} +EXPORT_SYMBOL_GPL(log_post_read_mmio); +EXPORT_TRACEPOINT_SYMBOL_GPL(rwmmio_post_read); +#endif /* CONFIG_TRACE_MMIO_ACCESS */ -- cgit v1.3.1