kernel/linux.git/tools/testing/selftests/bpf, branch v7.0-rc7

selftests/bpf: Add more precision tracking tests for atomics

2026-04-02T16:57:59+00:00

Add verifier precision tracking tests for BPF atomic fetch operations. Validate that backtrack_insn correctly propagates precision from the fetch dst_reg to the stack slot for {fetch_add,xchg,cmpxchg} atomics. For the first two src_reg gets the old memory value, and for the last one r0. The fetched register is used for pointer arithmetic to trigger backtracking. Also add coverage for fetch_{or,and,xor} flavors which exercises the bitwise atomic fetch variants going through the same insn->imm & BPF_FETCH check but with different imm values. Add dual-precision regression tests for fetch_add and cmpxchg where both the fetched value and a reread of the same stack slot are tracked for precision. After the atomic operation, the stack slot is STACK_MISC, so the ldx does not set INSN_F_STACK_ACCESS. These tests verify that stack precision propagates solely through the atomic fetch's load side. Add map-based tests for fetch_add and cmpxchg which validate that non- stack atomic fetch completes precision tracking without falling back to mark_all_scalars_precise. Lastly, add 32-bit variants for {fetch_add, cmpxchg} on map values to cover the second valid atomic operand size. # LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh -- ./test_progs -t verifier_precision [...] + /etc/rcS.d/S50-startup ./test_progs -t verifier_precision [ 1.697105] bpf_testmod: loading out-of-tree module taints kernel. [ 1.700220] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel [ 1.777043] tsc: Refined TSC clocksource calibration: 3407.986 MHz [ 1.777619] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc6d7268, max_idle_ns: 440795260133 ns [ 1.778658] clocksource: Switched to clocksource tsc #633/1 verifier_precision/bpf_neg:OK #633/2 verifier_precision/bpf_end_to_le:OK #633/3 verifier_precision/bpf_end_to_be:OK #633/4 verifier_precision/bpf_end_bswap:OK #633/5 verifier_precision/bpf_load_acquire:OK #633/6 verifier_precision/bpf_store_release:OK #633/7 verifier_precision/state_loop_first_last_equal:OK #633/8 verifier_precision/bpf_cond_op_r10:OK #633/9 verifier_precision/bpf_cond_op_not_r10:OK #633/10 verifier_precision/bpf_atomic_fetch_add_precision:OK #633/11 verifier_precision/bpf_atomic_xchg_precision:OK #633/12 verifier_precision/bpf_atomic_fetch_or_precision:OK #633/13 verifier_precision/bpf_atomic_fetch_and_precision:OK #633/14 verifier_precision/bpf_atomic_fetch_xor_precision:OK #633/15 verifier_precision/bpf_atomic_cmpxchg_precision:OK #633/16 verifier_precision/bpf_atomic_fetch_add_dual_precision:OK #633/17 verifier_precision/bpf_atomic_cmpxchg_dual_precision:OK #633/18 verifier_precision/bpf_atomic_fetch_add_map_precision:OK #633/19 verifier_precision/bpf_atomic_cmpxchg_map_precision:OK #633/20 verifier_precision/bpf_atomic_fetch_add_32bit_precision:OK #633/21 verifier_precision/bpf_atomic_cmpxchg_32bit_precision:OK #633/22 verifier_precision/bpf_neg_2:OK #633/23 verifier_precision/bpf_neg_3:OK #633/24 verifier_precision/bpf_neg_4:OK #633/25 verifier_precision/bpf_neg_5:OK #633 verifier_precision:OK Summary: 1/25 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/r/20260331222020.401848-2-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov

selftests/bpf: Add a test cases for sync_linked_regs regarding zext propagation

2026-03-21T20:19:40+00:00

Add multiple test cases for linked register tracking with alu32 ops: - Add a test that checks sync_linked_regs() regarding reg->id (the linked target register) for BPF_ADD_CONST32 rather than known_reg->id (the branch register). - Add a test case for linked register tracking that exposes the cross-type sync_linked_regs() bug. One register uses alu32 (w7 += 1, BPF_ADD_CONST32) and another uses alu64 (r8 += 2, BPF_ADD_CONST64), both linked to the same base register. - Add a test case that exercises regsafe() path pruning when two execution paths reach the same program point with linked registers carrying different ADD_CONST flags (BPF_ADD_CONST32 from alu32 vs BPF_ADD_CONST64 from alu64). This particular test passes with and without the fix since the pruning will fail due to different ranges, but it would still be useful to carry this one as a regression test for the unreachable div by zero. With the fix applied all the tests pass: # LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh -- ./test_progs -t verifier_linked_scalars [...] ./test_progs -t verifier_linked_scalars #602/1 verifier_linked_scalars/scalars: find linked scalars:OK #602/2 verifier_linked_scalars/sync_linked_regs_preserves_id:OK #602/3 verifier_linked_scalars/scalars_neg:OK #602/4 verifier_linked_scalars/scalars_neg_sub:OK #602/5 verifier_linked_scalars/scalars_neg_alu32_add:OK #602/6 verifier_linked_scalars/scalars_neg_alu32_sub:OK #602/7 verifier_linked_scalars/scalars_pos:OK #602/8 verifier_linked_scalars/scalars_sub_neg_imm:OK #602/9 verifier_linked_scalars/scalars_double_add:OK #602/10 verifier_linked_scalars/scalars_sync_delta_overflow:OK #602/11 verifier_linked_scalars/scalars_sync_delta_overflow_large_range:OK #602/12 verifier_linked_scalars/scalars_alu32_big_offset:OK #602/13 verifier_linked_scalars/scalars_alu32_basic:OK #602/14 verifier_linked_scalars/scalars_alu32_wrap:OK #602/15 verifier_linked_scalars/scalars_alu32_zext_linked_reg:OK #602/16 verifier_linked_scalars/scalars_alu32_alu64_cross_type:OK #602/17 verifier_linked_scalars/scalars_alu32_alu64_regsafe_pruning:OK #602/18 verifier_linked_scalars/alu32_negative_offset:OK #602/19 verifier_linked_scalars/spurious_precision_marks:OK #602 verifier_linked_scalars:OK Summary: 1/19 PASSED, 0 SKIPPED, 0 FAILED Co-developed-by: Puranjay Mohan Signed-off-by: Puranjay Mohan Signed-off-by: Daniel Borkmann Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260319211507.213816-2-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov

selftests/bpf: Add tests for maybe_fork_scalars() OR vs AND handling

2026-03-21T20:14:28+00:00

Add three test cases to verifier_bounds.c to verify that maybe_fork_scalars() correctly tracks register values for BPF_OR operations with constant source operands: 1. or_scalar_fork_rejects_oob: After ARSH 63 + OR 8, the pushed path should have dst = 8. With value_size = 8, accessing map_value + 8 is out of bounds and must be rejected. 2. and_scalar_fork_still_works: Regression test ensuring AND forking continues to work. ARSH 63 + AND 4 produces pushed dst = 0 and current dst = 4, both within value_size = 8. 3. or_scalar_fork_allows_inbounds: After ARSH 63 + OR 4, the pushed path has dst = 4, which is within value_size = 8 and should be accepted. These tests exercise the fix in the previous patch, which makes the pushed path re-execute the ALU instruction so it computes the correct result for BPF_OR. Signed-off-by: Daniel Wade Reviewed-by: Amery Hung Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260314021521.128361-3-danjwade95@gmail.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Add tests for sdiv32/smod32 with INT_MIN dividend

2026-03-21T20:12:17+00:00

Add tests to verify that signed 32-bit division and modulo operations produce correct results when the dividend is INT_MIN (0x80000000). The bug fixed in the previous commit only affects the BPF interpreter path. When JIT is enabled (the default on most architectures), the native CPU division instruction produces the correct result and these tests pass regardless. With bpf_jit_enable=0, the interpreter is used and without the previous fix, INT_MIN / 2 incorrectly returns 0x40000000 instead of 0xC0000000 due to abs(S32_MIN) undefined behavior, causing these tests to fail. Test cases: - SDIV32 INT_MIN / 2 = -1073741824 (imm and reg divisor) - SMOD32 INT_MIN % 2 = 0 (positive and negative divisor) Reviewed-by: Jiayuan Chen Acked-by: Yonghong Song Signed-off-by: Jenny Guanni Qu Link: https://lore.kernel.org/r/20260311011116.2108005-3-qguanni@gmail.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Add tests for bpf_throw lock leak from subprogs

2026-03-21T19:51:44+00:00

Add test cases to ensure the verifier correctly rejects bpf_throw from subprogs when RCU, preempt, or IRQ locks are held: * reject_subprog_rcu_lock_throw: subprog acquires bpf_rcu_read_lock and then calls bpf_throw * reject_subprog_throw_preempt_lock: always-throwing subprog called while caller holds bpf_preempt_disable * reject_subprog_throw_irq_lock: always-throwing subprog called while caller holds bpf_local_irq_save Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Ihor Solodrai Acked-by: Yonghong Song Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260320000809.643798-2-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov

bpf: Fix exception exit lock checking for subprogs

2026-03-21T19:51:44+00:00

process_bpf_exit_full() passes check_lock = !curframe to check_resource_leak(), which is false in cases when bpf_throw() is called from a static subprog. This makes check_resource_leak() to skip validation of active_rcu_locks, active_preempt_locks, and active_irq_id on exception exits from subprogs. At runtime bpf_throw() unwinds the stack via ORC without releasing any user-acquired locks, which may cause various issues as the result. Fix by setting check_lock = true for exception exits regardless of curframe, since exceptions bypass all intermediate frame cleanup. Update the error message prefix to "bpf_throw" for exception exits to distinguish them from normal BPF_EXIT. Fix reject_subprog_with_rcu_read_lock test which was previously passing for the wrong reason. Test program returned directly from the subprog call without closing the RCU section, so the error was triggered by the unclosed RCU lock on normal exit, not by bpf_throw. Update __msg annotations for affected tests to match the new "bpf_throw" error prefix. The spin_lock case is not affected because they are already checked [1] at the call site in do_check_insn() before bpf_throw can run. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/bpf/verifier.c?h=v7.0-rc4#n21098 Assisted-by: Claude:claude-opus-4-6 Fixes: f18b03fabaa9 ("bpf: Implement BPF exceptions") Signed-off-by: Ihor Solodrai Acked-by: Yonghong Song Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260320000809.643798-1-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov

selftests/bpf: Fix pkg-config call on static builds

2026-03-10T19:04:00+00:00

For commit b0dcdcb9ae75 ("resolve_btfids: Fix linker flags detection"), I suggested setting HOSTPKG_CONFIG to $PKG_CONFIG when compiling resolve_btfids, but I forgot the quotes around that variable. As a result, when running vmtest.sh with static linking, it fails as follows: $ LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh [...] make: unrecognized option '--static' Usage: make [options] [target] ... [...] This worked when I tested it because HOSTPKG_CONFIG didn't have a default value in the resolve_btfids Makefile, but once it does, the quotes aren't preserved and it fails on the next make call. Fixes: b0dcdcb9ae75 ("resolve_btfids: Fix linker flags detection") Signed-off-by: Paul Chaignon Acked-by: Mykyta Yatsenko Acked-by: Ihor Solodrai Link: https://lore.kernel.org/r/abADBwn_ykblpABE@mail.gmail.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Add test for BPF_END register ID reset

2026-03-10T18:46:31+00:00

Add a test case to ensure that BPF_END operations correctly break register's scalar ID ties. The test creates a scenario where r1 is a copy of r0, r0 undergoes a byte swap, and then r0 is checked against a constant. - Without the fix in the verifier, the bounds learned from r0 are incorrectly propagated to r1, making the verifier believe r1 is bounded and wrongly allowing subsequent pointer arithmetic. - With the fix, r1 remains an unbounded scalar, and the verifier correctly rejects the arithmetic operation between the frame pointer and the unbounded register. Co-developed-by: Tianci Cao Signed-off-by: Tianci Cao Co-developed-by: Shenghao Yuan Signed-off-by: Shenghao Yuan Signed-off-by: Yazhou Tang Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260304083228.142016-3-tangyazhou@zju.edu.cn Signed-off-by: Alexei Starovoitov

Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2026-03-07T20:20:37+00:00

Pull bpf fixes from Alexei Starovoitov: - Fix u32/s32 bounds when ranges cross min/max boundary (Eduard Zingerman) - Fix precision backtracking with linked registers (Eduard Zingerman) - Fix linker flags detection for resolve_btfids (Ihor Solodrai) - Fix race in update_ftrace_direct_add/del (Jiri Olsa) - Fix UAF in bpf_trampoline_link_cgroup_shim (Lang Xu) * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: resolve_btfids: Fix linker flags detection selftests/bpf: add reproducer for spurious precision propagation through calls bpf: collect only live registers in linked regs Revert "selftests/bpf: Update reg_bound range refinement logic" selftests/bpf: test refining u32/s32 bounds when ranges cross min/max boundary bpf: Fix u32/s32 bounds when ranges cross min/max boundary bpf: Fix a UAF issue in bpf_trampoline_link_cgroup_shim ftrace: Add missing ftrace_lock to update_ftrace_direct_add/del

resolve_btfids: Fix linker flags detection

2026-03-07T16:51:51+00:00

The "|| echo -lzstd" default makes zstd an unconditional link dependency of resolve_btfids. On systems where libzstd-dev is not installed and pkg-config fails, the linker fails: ld: cannot find -lzstd: No such file or directory libzstd is a transitive dependency of libelf, so the -lzstd flag is strictly necessary only for static builds [1]. Remove ZSTD_LIBS variable, and instead set LIBELF_LIBS depending on whether the build is static or not. Use $(HOSTPKG_CONFIG) as primary source of the flags list. Also add a default value for HOSTPKG_CONFIG in case it's not built via the toplevel Makefile. Pass it from selftests/bpf too. [1] https://lore.kernel.org/bpf/4ff82800-2daa-4b9f-95a9-6f512859ee70@linux.dev/ Reported-by: BPF CI Bot (Claude Opus 4.6) Reported-by: Vitaly Chikunov Closes: https://lore.kernel.org/bpf/aaWqMcK-2AQw5dx8@altlinux.org/ Fixes: 4021848a903e ("selftests/bpf: Pass through build flags to bpftool and resolve_btfids") Signed-off-by: Ihor Solodrai Reviewed-by: Paul Chaignon Link: https://lore.kernel.org/r/20260305014730.3123382-1-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov