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/test_debug_virtual.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 lib/test_debug_virtual.c (limited to 'lib/test_debug_virtual.c') diff --git a/lib/test_debug_virtual.c b/lib/test_debug_virtual.c new file mode 100644 index 000000000..518ee8d21 --- /dev/null +++ b/lib/test_debug_virtual.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#ifdef CONFIG_MIPS +#include +#endif + +struct foo { + unsigned int bar; +}; + +static struct foo *foo; + +static int __init test_debug_virtual_init(void) +{ + phys_addr_t pa; + void *va; + + va = (void *)VMALLOC_START; + pa = virt_to_phys(va); + + pr_info("PA: %pa for VA: 0x%lx\n", &pa, (unsigned long)va); + + foo = kzalloc_obj(*foo); + if (!foo) + return -ENOMEM; + + pa = virt_to_phys(foo); + va = foo; + pr_info("PA: %pa for VA: 0x%lx\n", &pa, (unsigned long)va); + + return 0; +} +module_init(test_debug_virtual_init); + +static void __exit test_debug_virtual_exit(void) +{ + kfree(foo); +} +module_exit(test_debug_virtual_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Test module for CONFIG_DEBUG_VIRTUAL"); -- cgit v1.3.1