| Message ID | 20221025184524.3526117-1-martin.lau@linux.dev (mailing list archive) |
|---|---|
| Headers | show |
| Series | bpf: Avoid unnecessary deadlock detection and failure in task storage | expand |
Hello: This series was applied to bpf/bpf-next.git (master) by Alexei Starovoitov <ast@kernel.org>: On Tue, 25 Oct 2022 11:45:15 -0700 you wrote: > From: Martin KaFai Lau <martin.lau@kernel.org> > > The commit bc235cdb423a ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]") > added deadlock detection to avoid a tracing program from recurring > on the bpf_task_storage_{get,delete}() helpers. These helpers acquire > a spin lock and it will lead to deadlock. > > [...] Here is the summary with links: - [bpf-next,1/9] bpf: Remove prog->active check for bpf_lsm and bpf_iter https://git.kernel.org/bpf/bpf-next/c/271de525e1d7 - [bpf-next,2/9] bpf: Append _recur naming to the bpf_task_storage helper proto https://git.kernel.org/bpf/bpf-next/c/0593dd34e534 - [bpf-next,3/9] bpf: Refactor the core bpf_task_storage_get logic into a new function https://git.kernel.org/bpf/bpf-next/c/6d65500c34d8 - [bpf-next,4/9] bpf: Avoid taking spinlock in bpf_task_storage_get if potential deadlock is detected https://git.kernel.org/bpf/bpf-next/c/e8b02296a6b8 - [bpf-next,5/9] bpf: Add new bpf_task_storage_get proto with no deadlock detection https://git.kernel.org/bpf/bpf-next/c/4279adb094a1 - [bpf-next,6/9] bpf: bpf_task_storage_delete_recur does lookup first before the deadlock check https://git.kernel.org/bpf/bpf-next/c/fda64ae0bb3e - [bpf-next,7/9] bpf: Add new bpf_task_storage_delete proto with no deadlock detection https://git.kernel.org/bpf/bpf-next/c/8a7dac37f27a - [bpf-next,8/9] selftests/bpf: Ensure no task storage failure for bpf_lsm.s prog due to deadlock detection https://git.kernel.org/bpf/bpf-next/c/0334b4d8822a - [bpf-next,9/9] selftests/bpf: Tracing prog can still do lookup under busy lock https://git.kernel.org/bpf/bpf-next/c/387b532138ee You are awesome, thank you!
From: Martin KaFai Lau <martin.lau@kernel.org> The commit bc235cdb423a ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]") added deadlock detection to avoid a tracing program from recurring on the bpf_task_storage_{get,delete}() helpers. These helpers acquire a spin lock and it will lead to deadlock. It is unnecessary for the bpf_lsm and bpf_iter programs which do not recur. The situation is the same as the existing bpf_pid_task_storage_{lookup,delete}_elem() which are used in the syscall and they also do not have deadlock detection. This set is to add new bpf_task_storage_{get,delete}() helper proto without the deadlock detection. The set also removes the prog->active check from the bpf_lsm and bpf_iter program. Please see the individual patch for details. Martin KaFai Lau (9): bpf: Remove prog->active check for bpf_lsm and bpf_iter bpf: Append _recur naming to the bpf_task_storage helper proto bpf: Refactor the core bpf_task_storage_get logic into a new function bpf: Avoid taking spinlock in bpf_task_storage_get if potential deadlock is detected bpf: Add new bpf_task_storage_get proto with no deadlock detection bpf: bpf_task_storage_delete_recur does lookup first before the deadlock check bpf: Add new bpf_task_storage_delete proto with no deadlock detection selftests/bpf: Ensure no task storage failure for bpf_lsm.s prog due to deadlock detection selftests/bpf: Tracing prog can still do lookup under busy lock arch/arm64/net/bpf_jit_comp.c | 9 +- arch/x86/net/bpf_jit_comp.c | 19 +-- include/linux/bpf.h | 26 ++-- include/linux/bpf_verifier.h | 15 +- kernel/bpf/bpf_local_storage.c | 1 + kernel/bpf/bpf_task_storage.c | 119 +++++++++++--- kernel/bpf/syscall.c | 5 +- kernel/bpf/trampoline.c | 80 ++++++++-- kernel/trace/bpf_trace.c | 5 + .../bpf/prog_tests/task_local_storage.c | 146 +++++++++++++++++- .../selftests/bpf/progs/task_ls_recursion.c | 43 +++++- .../bpf/progs/task_storage_nodeadlock.c | 47 ++++++ 12 files changed, 431 insertions(+), 84 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/task_storage_nodeadlock.c