- 22 Sep, 2022 20 commits
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Kumar Kartikeya Dwivedi authored
Instead of forcing all arguments to be referenced pointers with non-zero reg->ref_obj_id, tweak the definition of KF_TRUSTED_ARGS to mean that only PTR_TO_BTF_ID (and socket types translated to PTR_TO_BTF_ID) have that constraint, and require their offset to be set to 0. The rest of pointer types are also accomodated in this definition of trusted pointers, but with more relaxed rules regarding offsets. The inherent meaning of setting this flag is that all kfunc pointer arguments have a guranteed lifetime, and kernel object pointers (PTR_TO_BTF_ID, PTR_TO_CTX) are passed in their unmodified form (with offset 0). In general, this is not true for PTR_TO_BTF_ID as it can be obtained using pointer walks. Signed-off-by:
Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by:
Lorenzo Bianconi <lorenzo@kernel.org> Link: https://lore.kernel.org/r/cdede0043c47ed7a357f0a915d16f9ce06a1d589.1663778601.git.lorenzo@kernel.orgSigned-off-by:
Alexei Starovoitov <ast@kernel.org>
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Hou Tao authored
For a non-preallocated hash map on RT kernel, regular spinlock instead of raw spinlock is used for bucket lock. The reason is that on RT kernel memory allocation is forbidden under atomic context and regular spinlock is sleepable under RT. Now hash map has been fully converted to use bpf_map_alloc, and there will be no synchronous memory allocation for non-preallocated hash map, so it is safe to always use raw spinlock for bucket lock on RT. So removing the usage of htab_use_raw_lock() and updating the comments accordingly. Signed-off-by:
Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20220921073826.2365800-1-houtao@huaweicloud.comSigned-off-by:
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Jiri Olsa authored
We got report from sysbot [1] about warnings that were caused by bpf program attached to contention_begin raw tracepoint triggering the same tracepoint by using bpf_trace_printk helper that takes trace_printk_lock lock. Call Trace: <TASK> ? trace_event_raw_event_bpf_trace_printk+0x5f/0x90 bpf_trace_printk+0x2b/0xe0 bpf_prog_a9aec6167c091eef_prog+0x1f/0x24 bpf_trace_run2+0x26/0x90 native_queued_spin_lock_slowpath+0x1c6/0x2b0 _raw_spin_lock_irqsave+0x44/0x50 bpf_trace_printk+0x3f/0xe0 bpf_prog_a9aec6167c091eef_prog+0x1f/0x24 bpf_trace_run2+0x26/0x90 native_queued_spin_lock_slowpath+0x1c6/0x2b0 _raw_spin_lock_irqsave+0x44/0x50 bpf_trace_printk+0x3f/0xe0 bpf_prog_a9aec6167c091eef_prog+0x1f/0x24 bpf_trace_run2+0x26/0x90 native_queued_spin_lock_slowpath+0x1c6/0x2b0 _raw_spin_lock_irqsave+0x44/0x50 bpf_trace_printk+0x3f/0xe0 bpf_prog_a9aec6167c091eef_prog+0x1f/0x24 bpf_trace_run2+0x26/0x90 native_queued_spin_lock_slowpath+0x1c6/0x2b0 _raw_spin_lock_irqsave+0x44/0x50 __unfreeze_partials+0x5b/0x160 ... The can be reproduced by attaching bpf program as raw tracepoint on contention_begin tracepoint. The bpf prog calls bpf_trace_printk helper. Then by running perf bench the spin lock code is forced to take slow path and call contention_begin tracepoint. Fixing this by skipping execution of the bpf program if it's already running, Using bpf prog 'active' field, which is being currently used by trampoline programs for the same reason. Moving bpf_prog_inc_misses_counter to syscall.c because trampoline.c is compiled in just for CONFIG_BPF_JIT option. Reviewed-by:
Stanislav Fomichev <sdf@google.com> Reported-by: syzbot+2251879aa068ad9c960d@syzkaller.appspotmail.com [1] https://lore.kernel.org/bpf/YxhFe3EwqchC%2FfYf@krava/T/#tSigned-off-by:
Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20220916071914.7156-1-jolsa@kernel.orgSigned-off-by:
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Alexei Starovoitov authored
Roberto Sassu says: ==================== One of the desirable features in security is the ability to restrict import of data to a given system based on data authenticity. If data import can be restricted, it would be possible to enforce a system-wide policy based on the signing keys the system owner trusts. This feature is widely used in the kernel. For example, if the restriction is enabled, kernel modules can be plugged in only if they are signed with a key whose public part is in the primary or secondary keyring. For eBPF, it can be useful as well. For example, it might be useful to authenticate data an eBPF program makes security decisions on. After a discussion in the eBPF mailing list, it was decided that the stated goal should be accomplished by introducing four new kfuncs: bpf_lookup_user_key() and bpf_lookup_system_key(), for retrieving a keyring with keys trusted for signature verification, respectively from its serial and from a pre-determined ID; bpf_key_put(), to release the reference obtained with the former two kfuncs, bpf_verify_pkcs7_signature(), for verifying PKCS#7 signatures. Other than the key serial, bpf_lookup_user_key() also accepts key lookup flags, that influence the behavior of the lookup. bpf_lookup_system_key() accepts pre-determined IDs defined in include/linux/verification.h. bpf_key_put() accepts the new bpf_key structure, introduced to tell whether the other structure member, a key pointer, is valid or not. The reason is that verify_pkcs7_signature() also accepts invalid pointers, set with the pre-determined ID, to select a system-defined keyring. key_put() must be called only for valid key pointers. Since the two key lookup functions allocate memory and one increments a key reference count, they must be used in conjunction with bpf_key_put(). The latter must be called only if the lookup functions returned a non-NULL pointer. The verifier denies the execution of eBPF programs that don't respect this rule. The two key lookup functions should be used in alternative, depending on the use case. While bpf_lookup_user_key() provides great flexibility, it seems suboptimal in terms of security guarantees, as even if the eBPF program is assumed to be trusted, the serial used to obtain the key pointer might come from untrusted user space not choosing one that the system administrator approves to enforce a mandatory policy. bpf_lookup_system_key() instead provides much stronger guarantees, especially if the pre-determined ID is not passed by user space but is hardcoded in the eBPF program, and that program is signed. In this case, bpf_verify_pkcs7_signature() will always perform signature verification with a key that the system administrator approves, i.e. the primary, secondary or platform keyring. Nevertheless, key permission checks need to be done accurately. Since bpf_lookup_user_key() cannot determine how a key will be used by other kfuncs, it has to defer the permission check to the actual kfunc using the key. It does it by calling lookup_user_key() with KEY_DEFER_PERM_CHECK as needed permission. Later, bpf_verify_pkcs7_signature(), if called, completes the permission check by calling key_validate(). It does not need to call key_task_permission() with permission KEY_NEED_SEARCH, as it is already done elsewhere by the key subsystem. Future kfuncs using the bpf_key structure need to implement the proper checks as well. Finally, the last kfunc, bpf_verify_pkcs7_signature(), accepts the data and signature to verify as eBPF dynamic pointers, to minimize the number of kfunc parameters, and the keyring with keys for signature verification as a bpf_key structure, returned by one of the two key lookup functions. bpf_lookup_user_key() and bpf_verify_pkcs7_signature() can be called only from sleepable programs, because of memory allocation and crypto operations. For example, the lsm.s/bpf attach point is suitable, fexit/array_map_update_elem is not. The correctness of implementation of the new kfuncs and of their usage is checked with the introduced tests. The patch set includes a patch from another author (dependency) for sake of completeness. It is organized as follows. Patch 1 from KP Singh allows kfuncs to be used by LSM programs. Patch 2 exports the bpf_dynptr definition through BTF. Patch 3 splits is_dynptr_reg_valid_init() and introduces is_dynptr_type_expected(), to know more precisely the cause of a negative result of a dynamic pointer check. Patch 4 allows dynamic pointers to be used as kfunc parameters. Patch 5 exports bpf_dynptr_get_size(), to obtain the real size of data carried by a dynamic pointer. Patch 6 makes available for new eBPF kfuncs and programs some key-related definitions. Patch 7 introduces the bpf_lookup_*_key() and bpf_key_put() kfuncs. Patch 8 introduces the bpf_verify_pkcs7_signature() kfunc. Patch 9 changes the testing kernel configuration to compile everything as built-in. Finally, patches 10-13 introduce the tests. Changelog v17: - Remove unnecessary typedefs in test_verify_pkcs7_sig.c (suggested by KP) - Add patch to export bpf_dynptr through BTF (reported by KP) - Rename u{8,16,32,64} variables to __u{8,16,32,64} in the tests, for consistency with other eBPF programs (suggested by Yonghong) v16: - Remove comments in include/linux/key.h for KEY_LOOKUP_* - Change kmalloc() flag from GFP_ATOMIC to GFP_KERNEL in bpf_lookup_user_key(), as the kfunc needs anyway to be sleepable (suggested by Kumar) - Test passing a dynamic pointer with NULL data to bpf_verify_pkcs7_signature() (suggested by Kumar) v15: - Add kfunc_dynptr_param test to deny list for s390x v14: - Explain that is_dynptr_type_expected() will be useful also for BTF (suggested by Joanne) - Rename KEY_LOOKUP_FLAGS_ALL to KEY_LOOKUP_ALL (suggested by Jarkko) - Swap declaration of spi and dynptr_type in is_dynptr_type_expected() (suggested by Joanne) - Reimplement kfunc dynptr tests with a regular eBPF program instead of executing them with test_verifier (suggested by Joanne) - Make key lookup flags as enum so that they are automatically exported through BTF (suggested by Alexei) v13: - Split is_dynptr_reg_valid_init() and introduce is_dynptr_type_expected() to see if the dynamic pointer type passed as argument to a kfunc is supported (suggested by Kumar) - Add forward declaration of struct key in include/linux/bpf.h (suggested by Song) - Declare mask for key lookup flags, remove key_lookup_flags_check() (suggested by Jarkko and KP) - Allow only certain dynamic pointer types (currently, local) to be passed as argument to kfuncs (suggested by Kumar) - For each dynamic pointer parameter in kfunc, additionally check if the passed pointer is to the stack (suggested by Kumar) - Split the validity/initialization and dynamic pointer type check also in the verifier, and adjust the expected error message in the test (a test for an unexpected dynptr type passed to a helper cannot be added due to missing suitable helpers, but this case has been tested manually) - Add verifier tests to check the dynamic pointers passed as argument to kfuncs (suggested by Kumar) v12: - Put lookup_key and verify_pkcs7_sig tests in deny list for s390x (JIT does not support calling kernel function) v11: - Move stringify_struct() macro to include/linux/btf.h (suggested by Daniel) - Change kernel configuration options in tools/testing/selftests/bpf/config* from =m to =y v10: - Introduce key_lookup_flags_check() and system_keyring_id_check() inline functions to check parameters (suggested by KP) - Fix descriptions and comment of key-related kfuncs (suggested by KP) - Register kfunc set only once (suggested by Alexei) - Move needed kernel options to the architecture-independent configuration for testing v9: - Drop patch to introduce KF_SLEEPABLE kfunc flag (already merged) - Rename valid_ptr member of bpf_key to has_ref (suggested by Daniel) - Check dynamic pointers in kfunc definition with bpf_dynptr_kern struct definition instead of string, to detect structure renames (suggested by Daniel) - Explicitly say that we permit initialized dynamic pointers in kfunc definition (suggested by Daniel) - Remove noinline __weak from kfuncs definition (reported by Daniel) - Simplify key lookup flags check in bpf_lookup_user_key() (suggested by Daniel) - Explain the reason for deferring key permission check (suggested by Daniel) - Allocate memory with GFP_ATOMIC in bpf_lookup_system_key(), and remove KF_SLEEPABLE kfunc flag from kfunc declaration (suggested by Daniel) - Define only one kfunc set and remove the loop for registration (suggested by Alexei) v8: - Define the new bpf_key structure to carry the key pointer and whether that pointer is valid or not (suggested by Daniel) - Drop patch to mark a kfunc parameter with the __maybe_null suffix - Improve documentation of kfuncs - Introduce bpf_lookup_system_key() to obtain a key pointer suitable for verify_pkcs7_signature() (suggested by Daniel) - Use the new kfunc registration API - Drop patch to test the __maybe_null suffix - Add tests for bpf_lookup_system_key() v7: - Add support for using dynamic and NULL pointers in kfunc (suggested by Alexei) - Add new kfunc-related tests v6: - Switch back to key lookup helpers + signature verification (until v5), and defer permission check from bpf_lookup_user_key() to bpf_verify_pkcs7_signature() - Add additional key lookup test to illustrate the usage of the KEY_LOOKUP_CREATE flag and validate the flags (suggested by Daniel) - Make description of flags of bpf_lookup_user_key() more user-friendly (suggested by Daniel) - Fix validation of flags parameter in bpf_lookup_user_key() (reported by Daniel) - Rename bpf_verify_pkcs7_signature() keyring-related parameters to user_keyring and system_keyring to make their purpose more clear - Accept keyring-related parameters of bpf_verify_pkcs7_signature() as alternatives (suggested by KP) - Replace unsigned long type with u64 in helper declaration (suggested by Daniel) - Extend the bpf_verify_pkcs7_signature() test by calling the helper without data, by ensuring that the helper enforces the keyring-related parameters as alternatives, by ensuring that the helper rejects inaccessible and expired keyrings, and by checking all system keyrings - Move bpf_lookup_user_key() and bpf_key_put() usage tests to ref_tracking.c (suggested by John) - Call bpf_lookup_user_key() and bpf_key_put() only in sleepable programs v5: - Move KEY_LOOKUP_ to include/linux/key.h for validation of bpf_verify_pkcs7_signature() parameter - Remove bpf_lookup_user_key() and bpf_key_put() helpers, and the corresponding tests - Replace struct key parameter of bpf_verify_pkcs7_signature() with the keyring serial and lookup flags - Call lookup_user_key() and key_put() in bpf_verify_pkcs7_signature() code, to ensure that the retrieved key is used according to the permission requested at lookup time - Clarified keyring precedence in the description of bpf_verify_pkcs7_signature() (suggested by John) - Remove newline in the second argument of ASSERT_ - Fix helper prototype regular expression in bpf_doc.py v4: - Remove bpf_request_key_by_id(), don't return an invalid pointer that other helpers can use - Pass the keyring ID (without ULONG_MAX, suggested by Alexei) to bpf_verify_pkcs7_signature() - Introduce bpf_lookup_user_key() and bpf_key_put() helpers (suggested by Alexei) - Add lookup_key_norelease test, to ensure that the verifier blocks eBPF programs which don't decrement the key reference count - Parse raw PKCS#7 signature instead of module-style signature in the verify_pkcs7_signature test (suggested by Alexei) - Parse kernel module in user space and pass raw PKCS#7 signature to the eBPF program for signature verification v3: - Rename bpf_verify_signature() back to bpf_verify_pkcs7_signature() to avoid managing different parameters for each signature verification function in one helper (suggested by Daniel) - Use dynamic pointers and export bpf_dynptr_get_size() (suggested by Alexei) - Introduce bpf_request_key_by_id() to give more flexibility to the caller of bpf_verify_pkcs7_signature() to retrieve the appropriate keyring (suggested by Alexei) - Fix test by reordering the gcc command line, always compile sign-file - Improve helper support check mechanism in the test v2: - Rename bpf_verify_pkcs7_signature() to a more generic bpf_verify_signature() and pass the signature type (suggested by KP) - Move the helper and prototype declaration under #ifdef so that user space can probe for support for the helper (suggested by Daniel) - Describe better the keyring types (suggested by Daniel) - Include linux/bpf.h instead of vmlinux.h to avoid implicit or redeclaration - Make the test selfcontained (suggested by Alexei) v1: - Don't define new map flag but introduce simple wrapper of verify_pkcs7_signature() (suggested by Alexei and KP) ==================== Signed-off-by: -
Roberto Sassu authored
Add tests to ensure that only supported dynamic pointer types are accepted, that the passed argument is actually a dynamic pointer, that the passed argument is a pointer to the stack, and that bpf_verify_pkcs7_signature() correctly handles dynamic pointers with data set to NULL. The tests are currently in the deny list for s390x (JIT does not support calling kernel function). Signed-off-by:
Roberto Sassu <roberto.sassu@huawei.com> Acked-by:
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Roberto Sassu authored
Perform several tests to ensure the correct implementation of the bpf_verify_pkcs7_signature() kfunc. Do the tests with data signed with a generated testing key (by using sign-file from scripts/) and with the tcp_bic.ko kernel module if it is found in the system. The test does not fail if tcp_bic.ko is not found. First, perform an unsuccessful signature verification without data. Second, perform a successful signature verification with the session keyring and a new one created for testing. Then, ensure that permission and validation checks are done properly on the keyring provided to bpf_verify_pkcs7_signature(), despite those checks were deferred at the time the keyring was retrieved with bpf_lookup_user_key(). The tests expect to encounter an error if the Search permission is removed from the keyring, or the keyring is expired. Finally, perform a successful and unsuccessful signature verification with the keyrings with pre-determined IDs (the last test fails because the key is not in the platform keyring). The test is currently in the deny list for s390x (JIT does not support calling kernel function). Signed-off-by:
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Roberto Sassu authored
Add a test to ensure that bpf_lookup_user_key() creates a referenced special keyring when the KEY_LOOKUP_CREATE flag is passed to this function. Ensure that the kfunc rejects invalid flags. Ensure that a keyring can be obtained from bpf_lookup_system_key() when one of the pre-determined keyring IDs is provided. The test is currently blacklisted for s390x (JIT does not support calling kernel function). Signed-off-by:
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Roberto Sassu authored
Add verifier tests for bpf_lookup_*_key() and bpf_key_put(), to ensure that acquired key references stored in the bpf_key structure are released, that a non-NULL bpf_key pointer is passed to bpf_key_put(), and that key references are not leaked. Also, slightly modify test_verifier.c, to find the BTF ID of the attach point for the LSM program type (currently, it is done only for TRACING). Signed-off-by:
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Roberto Sassu authored
Since the eBPF CI does not support kernel modules, change the kernel config to compile everything as built-in. Signed-off-by:
Daniel Müller <deso@posteo.net> Acked-by:
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Roberto Sassu authored
Add the bpf_verify_pkcs7_signature() kfunc, to give eBPF security modules the ability to check the validity of a signature against supplied data, by using user-provided or system-provided keys as trust anchor. The new kfunc makes it possible to enforce mandatory policies, as eBPF programs might be allowed to make security decisions only based on data sources the system administrator approves. The caller should provide the data to be verified and the signature as eBPF dynamic pointers (to minimize the number of parameters) and a bpf_key structure containing a reference to the keyring with keys trusted for signature verification, obtained from bpf_lookup_user_key() or bpf_lookup_system_key(). For bpf_key structures obtained from the former lookup function, bpf_verify_pkcs7_signature() completes the permission check deferred by that function by calling key_validate(). key_task_permission() is already called by the PKCS#7 code. Signed-off-by:
KP Singh <kpsingh@kernel.org> Acked-by:
Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20220920075951.929132-9-roberto.sassu@huaweicloud.comSigned-off-by:
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Roberto Sassu authored
Add the bpf_lookup_user_key(), bpf_lookup_system_key() and bpf_key_put() kfuncs, to respectively search a key with a given key handle serial number and flags, obtain a key from a pre-determined ID defined in include/linux/verification.h, and cleanup. Introduce system_keyring_id_check() to validate the keyring ID parameter of bpf_lookup_system_key(). Signed-off-by:
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Roberto Sassu authored
In preparation for the patch that introduces the bpf_lookup_user_key() eBPF kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be able to validate the kfunc parameters. Add them to enum key_lookup_flag, so that all the current ones and the ones defined in the future are automatically exported through BTF and available to eBPF programs. Also, add KEY_LOOKUP_ALL to the enum, with the logical OR of currently defined flags as value, to facilitate checking whether a variable contains only those flags. Signed-off-by:
Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/r/20220920075951.929132-7-roberto.sassu@huaweicloud.comSigned-off-by:
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Roberto Sassu authored
Export bpf_dynptr_get_size(), so that kernel code dealing with eBPF dynamic pointers can obtain the real size of data carried by this data structure. Signed-off-by:
Joanne Koong <joannelkoong@gmail.com> Acked-by:
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Roberto Sassu authored
Allow dynamic pointers (struct bpf_dynptr_kern *) to be specified as parameters in kfuncs. Also, ensure that dynamic pointers passed as argument are valid and initialized, are a pointer to the stack, and of the type local. More dynamic pointer types can be supported in the future. To properly detect whether a parameter is of the desired type, introduce the stringify_struct() macro to compare the returned structure name with the desired name. In addition, protect against structure renames, by halting the build with BUILD_BUG_ON(), so that developers have to revisit the code. To check if a dynamic pointer passed to the kfunc is valid and initialized, and if its type is local, export the existing functions is_dynptr_reg_valid_init() and is_dynptr_type_expected(). Cc: Joanne Koong <joannelkoong@gmail.com> Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by:
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Roberto Sassu authored
Move dynptr type check to is_dynptr_type_expected() from is_dynptr_reg_valid_init(), so that callers can better determine the cause of a negative result (dynamic pointer not valid/initialized, dynamic pointer of the wrong type). It will be useful for example for BTF, to restrict which dynamic pointer types can be passed to kfuncs, as initially only the local type will be supported. Also, splitting makes the code more readable, since checking the dynamic pointer type is not necessarily related to validity and initialization. Split the validity/initialization and dynamic pointer type check also in the verifier, and adjust the expected error message in the test (a test for an unexpected dynptr type passed to a helper cannot be added due to missing suitable helpers, but this case has been tested manually). Cc: Joanne Koong <joannelkoong@gmail.com> Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by:
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Roberto Sassu authored
eBPF dynamic pointers is a new feature recently added to upstream. It binds together a pointer to a memory area and its size. The internal kernel structure bpf_dynptr_kern is not accessible by eBPF programs in user space. They instead see bpf_dynptr, which is then translated to the internal kernel structure by the eBPF verifier. The problem is that it is not possible to include at the same time the uapi include linux/bpf.h and the vmlinux BTF vmlinux.h, as they both contain the definition of some structures/enums. The compiler complains saying that the structures/enums are redefined. As bpf_dynptr is defined in the uapi include linux/bpf.h, this makes it impossible to include vmlinux.h. However, in some cases, e.g. when using kfuncs, vmlinux.h has to be included. The only option until now was to include vmlinux.h and add the definition of bpf_dynptr directly in the eBPF program source code from linux/bpf.h. Solve the problem by using the same approach as for bpf_timer (which also follows the same scheme with the _kern suffix for the internal kernel structure). Add the following line in one of the dynamic pointer helpers, bpf_dynptr_from_mem(): BTF_TYPE_EMIT(struct bpf_dynptr); Cc: stable@vger.kernel.org Cc: Joanne Koong <joannelkoong@gmail.com> Fixes: 97e03f52 ("bpf: Add verifier support for dynptrs") Signed-off-by:
Yonghong Song <yhs@fb.com> Tested-by:
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KP Singh authored
In preparation for the addition of new kfuncs, allow kfuncs defined in the tracing subsystem to be used in LSM programs by mapping the LSM program type to the TRACING hook. Signed-off-by:
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Tao Chen authored
Currently, the default vmlinux files at '/boot/vmlinux-*', '/lib/modules/*/vmlinux-*' etc. are parsed with 'btf__parse_elf()' to extract BTF. It is possible that these files are actually raw BTF files similar to /sys/kernel/btf/vmlinux. So parse these files with 'btf__parse' which tries both raw format and ELF format. This might be useful in some scenarios where users put their custom BTF into known locations and don't want to specify btf_custom_path option. Signed-off-by:
Tao Chen <chentao.kernel@linux.alibaba.com> Signed-off-by:
Andrii Nakryiko <andrii@kernel.org> Acked-by:
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Yauheni Kaliuta authored
It's possible to specify particular tests for test_bpf.ko with module parameters. Make it possible to pass the module parameters, example: test_kmod.sh test_range=1,3 Since magnitude tests take long time it can be reasonable to skip them. Signed-off-by:
Yauheni Kaliuta <ykaliuta@redhat.com> Signed-off-by:
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Yonghong Song authored
Commit 34586d29 ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2 macro for trampoline based programs with struct arguments. Andrii made a few suggestions to improve code quality and description. This patch implemented these suggestions including better internal macro name, consistent usage pattern for __builtin_choose_expr(), simpler macro definition for always-inline func arguments and better macro description. Signed-off-by:
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- 21 Sep, 2022 8 commits
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Andrii Nakryiko authored
David Vernet says: ==================== This patch set defines a new map type, BPF_MAP_TYPE_USER_RINGBUF, which provides single-user-space-producer / single-kernel-consumer semantics over a ring buffer. Along with the new map type, a helper function called bpf_user_ringbuf_drain() is added which allows a BPF program to specify a callback with the following signature, to which samples are posted by the helper: void (struct bpf_dynptr *dynptr, void *context); The program can then use the bpf_dynptr_read() or bpf_dynptr_data() helper functions to safely read the sample from the dynptr. There are currently no helpers available to determine the size of the sample, but one could easily be added if required. On the user-space side, libbpf has been updated to export a new 'struct ring_buffer_user' type, along with the following symbols: struct ring_buffer_user * ring_buffer_user__new(int map_fd, const struct ring_buffer_user_opts *opts); void ring_buffer_user__free(struct ring_buffer_user *rb); void *ring_buffer_user__reserve(struct ring_buffer_user *rb, uint32_t size); void *ring_buffer_user__poll(struct ring_buffer_user *rb, uint32_t size, int timeout_ms); void ring_buffer_user__discard(struct ring_buffer_user *rb, void *sample); void ring_buffer_user__submit(struct ring_buffer_user *rb, void *sample); These symbols are exported for inclusion in libbpf version 1.0.0. Signed-off-by:David Vernet <void@manifault.com> --- v5 -> v6: - Fixed s/BPF_MAP_TYPE_RINGBUF/BPF_MAP_TYPE_USER_RINGBUF typo in the libbpf user ringbuf doxygen header comment for ring_buffer_user__new() (Andrii). - Specify that pointer returned from ring_buffer_user__reserve() and its blocking counterpart is 8-byte aligned (Andrii). - Renamed user_ringbuf__commit() to user_ringbuf_commit(), as it's static (Andrii). - Another slight reworking of user_ring_buffer__reserve_blocking() to remove some extraneous nanosecond variables + checking (Andrii). - Add a final check of user_ring_buffer__reserve() in user_ring_buffer__reserve_blocking(). - Moved busy bit lock / unlock logic from __bpf_user_ringbuf_peek() to bpf_user_ringbuf_drain() (Andrii). - -ENOSPC -> -ENODATA for an empty ring buffer in __bpf_user_ringbuf_peek() (Andrii). - Updated BPF_RB_FORCE_WAKEUP to only force a wakeup notification to be sent if even if no sample was drained. - Changed a bit of the wording in the UAPI header for bpf_user_ringbuf_drain() to mention the BPF_RB_FORCE_WAKEUP behavior. - Remove extra space after return in ringbuf_map_poll_user() (Andrii). - Removed now-extraneous paragraph from the commit summary of patch 2/4 (Andrii). v4 -> v5: - DENYLISTed the user-ringbuf test suite on s390x. We have a number of functions in the progs/user_ringbuf_success.c prog that user-space fires by invoking a syscall. Not all of these syscalls are available on s390x. If and when we add the ability to kick the kernel from user-space, or if we end up using iterators for that per Hao's suggestion, we could re-enable this test suite on s390x. - Fixed a few more places that needed ringbuffer -> ring buffer. v3 -> v4: - Update BPF_MAX_USER_RINGBUF_SAMPLES to not specify a bit, and instead just specify a number of samples. (Andrii) - Update "ringbuffer" in comments and commit summaries to say "ring buffer". (Andrii) - Return -E2BIG from bpf_user_ringbuf_drain() both when a sample can't fit into the ring buffer, and when it can't fit into a dynptr. (Andrii) - Don't loop over samples in __bpf_user_ringbuf_peek() if a sample was discarded. Instead, return -EAGAIN so the caller can deal with it. Also updated the caller to detect -EAGAIN and skip over it when iterating. (Andrii) - Removed the heuristic for notifying user-space when a sample is drained, causing the ring buffer to no longer be full. This may be useful in the future, but is being removed now because it's strictly a heuristic. - Re-add BPF_RB_FORCE_WAKEUP flag to bpf_user_ringbuf_drain(). (Andrii) - Remove helper_allocated_dynptr tracker from verifier. (Andrii) - Add libbpf function header comments to tools/lib/bpf/libbpf.h, so that they will be included in rendered libbpf docs. (Andrii) - Add symbols to a new LIBBPF_1.1.0 section in linker version script, rather than including them in LIBBPF_1.0.0. (Andrii) - Remove libbpf_err() calls from static libbpf functions. (Andrii) - Check user_ring_buffer_opts instead of ring_buffer_opts in user_ring_buffer__new(). (Andrii) - Avoid an extra if in the hot path in user_ringbuf__commit(). (Andrii) - Use ENOSPC rather than ENODATA if no space is available in the ring buffer. (Andrii) - Don't round sample size in header to 8, but still round size that is reserved and written to 8, and validate positions are multiples of 8 (Andrii). - Use nanoseconds for most calculations in user_ring_buffer__reserve_blocking(). (Andrii) - Don't use CHECK() in testcases, instead use ASSERT_*. (Andrii) - Use SEC("?raw_tp") instead of SEC("?raw_tp/sys_nanosleep") in negative test. (Andrii) - Move test_user_ringbuf.h header to live next to BPF program instead of a directory up from both it and the user-space test program. (Andrii) - Update bpftool help message / docs to also include user_ringbuf. v2 -> v3: - Lots of formatting fixes, such as keeping things on one line if they fit within 100 characters, and removing some extraneous newlines. Applies to all diffs in the patch-set. (Andrii) - Renamed ring_buffer_user__* symbols to user_ring_buffer__*. (Andrii) - Added a missing smb_mb__before_atomic() in __bpf_user_ringbuf_sample_release(). (Hao) - Restructure how and when notification events are sent from the kernel to the user-space producers via the .map_poll() callback for the BPF_MAP_TYPE_USER_RINGBUF map. Before, we only sent a notification when the ringbuffer was fully drained. Now, we guarantee user-space that we'll send an event at least once per bpf_user_ringbuf_drain(), as long as at least one sample was drained, and BPF_RB_NO_WAKEUP was not passed. As a heuristic, we also send a notification event any time a sample being drained causes the ringbuffer to no longer be full. (Andrii) - Continuing on the above point, updated user_ring_buffer__reserve_blocking() to loop around epoll_wait() until a sufficiently large sample is found. (Andrii) - Communicate BPF_RINGBUF_BUSY_BIT and BPF_RINGBUF_DISCARD_BIT in sample headers. The ringbuffer implementation still only supports single-producer semantics, but we can now add synchronization support in user_ring_buffer__reserve(), and will automatically get multi-producer semantics. (Andrii) - Updated some commit summaries, specifically adding more details where warranted. (Andrii) - Improved function documentation for bpf_user_ringbuf_drain(), more clearly explaining all function arguments and return types, as well as the semantics for waking up user-space producers. - Add function header comments for user_ring_buffer__reserve{_blocking}(). (Andrii) - Rounding-up all samples to 8-bytes in the user-space producer, and enforcing that all samples are properly aligned in the kernel. (Andrii) - Added testcases that verify that bpf_user_ringbuf_drain() properly validates samples, and returns error conditions if any invalid samples are encountered. (Andrii) - Move atomic_t busy field out of the consumer page, and into the struct bpf_ringbuf. (Andrii) - Split ringbuf_map_{mmap, poll}_{kern, user}() into separate implementations. (Andrii) - Don't silently consume errors in bpf_user_ringbuf_drain(). (Andrii) - Remove magic number of samples (4096) from bpf_user_ringbuf_drain(), and instead use BPF_MAX_USER_RINGBUF_SAMPLES macro, which allows 128k samples. (Andrii) - Remove MEM_ALLOC modifier from PTR_TO_DYNPTR register in verifier, and instead rely solely on the register being PTR_TO_DYNPTR. (Andrii) - Move freeing of atomic_t busy bit to before we invoke irq_work_queue() in __bpf_user_ringbuf_sample_release(). (Andrii) - Only check for BPF_RB_NO_WAKEUP flag in bpf_ringbuf_drain(). - Remove libbpf function names from kernel smp_{load, store}* comments in the kernel. (Andrii) - Don't use double-underscore naming convention in libbpf functions. (Andrii) - Use proper __u32 and __u64 for types where we need to guarantee their size. (Andrii) v1 -> v2: - Following Joanne landing 88374342 ("bpf: Fix ref_obj_id for dynptr data slices in verifier") [0], removed [PATCH 1/5] bpf: Clear callee saved regs after updating REG0 [1]. (Joanne) - Following the above adjustment, updated check_helper_call() to not store a reference for bpf_dynptr_data() if the register containing the dynptr is of type MEM_ALLOC. (Joanne) - Fixed casting issue pointed out by kernel test robot by adding a missing (uintptr_t) cast. (lkp) [0] https://lore.kernel.org/all/20220809214055.4050604-1-joannelkoong@gmail.com/ [1] https://lore.kernel.org/all/20220808155341.2479054-1-void@manifault.com/ ==================== Signed-off-by:
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David Vernet authored
This change includes selftests that validate the expected behavior and APIs of the new BPF_MAP_TYPE_USER_RINGBUF map type. Signed-off-by:
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David Vernet authored
Now that all of the logic is in place in the kernel to support user-space produced ring buffers, we can add the user-space logic to libbpf. This patch therefore adds the following public symbols to libbpf: struct user_ring_buffer * user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts); void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size); void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms); void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample); void user_ring_buffer__discard(struct user_ring_buffer *rb, void user_ring_buffer__free(struct user_ring_buffer *rb); A user-space producer must first create a struct user_ring_buffer * object with user_ring_buffer__new(), and can then reserve samples in the ring buffer using one of the following two symbols: void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size); void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms); With user_ring_buffer__reserve(), a pointer to a 'size' region of the ring buffer will be returned if sufficient space is available in the buffer. user_ring_buffer__reserve_blocking() provides similar semantics, but will block for up to 'timeout_ms' in epoll_wait if there is insufficient space in the buffer. This function has the guarantee from the kernel that it will receive at least one event-notification per invocation to bpf_ringbuf_drain(), provided that at least one sample is drained, and the BPF program did not pass the BPF_RB_NO_WAKEUP flag to bpf_ringbuf_drain(). Once a sample is reserved, it must either be committed to the ring buffer with user_ring_buffer__submit(), or discarded with user_ring_buffer__discard(). Signed-off-by: -
David Vernet authored
In a prior change, we added a new BPF_MAP_TYPE_USER_RINGBUF map type which will allow user-space applications to publish messages to a ring buffer that is consumed by a BPF program in kernel-space. In order for this map-type to be useful, it will require a BPF helper function that BPF programs can invoke to drain samples from the ring buffer, and invoke callbacks on those samples. This change adds that capability via a new BPF helper function: bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx, u64 flags) BPF programs may invoke this function to run callback_fn() on a series of samples in the ring buffer. callback_fn() has the following signature: long callback_fn(struct bpf_dynptr *dynptr, void *context); Samples are provided to the callback in the form of struct bpf_dynptr *'s, which the program can read using BPF helper functions for querying struct bpf_dynptr's. In order to support bpf_ringbuf_drain(), a new PTR_TO_DYNPTR register type is added to the verifier to reflect a dynptr that was allocated by a helper function and passed to a BPF program. Unlike PTR_TO_STACK dynptrs which are allocated on the stack by a BPF program, PTR_TO_DYNPTR dynptrs need not use reference tracking, as the BPF helper is trusted to properly free the dynptr before returning. The verifier currently only supports PTR_TO_DYNPTR registers that are also DYNPTR_TYPE_LOCAL. Note that while the corresponding user-space libbpf logic will be added in a subsequent patch, this patch does contain an implementation of the .map_poll() callback for BPF_MAP_TYPE_USER_RINGBUF maps. This .map_poll() callback guarantees that an epoll-waiting user-space producer will receive at least one event notification whenever at least one sample is drained in an invocation of bpf_user_ringbuf_drain(), provided that the function is not invoked with the BPF_RB_NO_WAKEUP flag. If the BPF_RB_FORCE_WAKEUP flag is provided, a wakeup notification is sent even if no sample was drained. Signed-off-by: -
David Vernet authored
We want to support a ringbuf map type where samples are published from user-space, to be consumed by BPF programs. BPF currently supports a kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF map type. We'll need to define a new map type for user-space -> kernel, as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply to a user-space producer ring buffer, and we'll want to add one or more helper functions that would not apply for a kernel-producer ring buffer. This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type definition. The map type is useless in its current form, as there is no way to access or use it for anything until we one or more BPF helpers. A follow-on patch will therefore add a new helper function that allows BPF programs to run callbacks on samples that are published to the ring buffer. Signed-off-by:
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William Dean authored
It could directly return 'btf_check_sec_info' to simplify code. Signed-off-by:
William Dean <williamsukatube@163.com> Acked-by:
Martin KaFai Lau <martin.lau@kernel.org>
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Xin Liu authored
We found that function btf_dump__dump_type_data can be called by the user as an API, but in this function, the `opts` parameter may be used as a null pointer.This causes `opts->indent_str` to trigger a NULL pointer exception. Fixes: 2ce8450e ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts") Signed-off-by:
Xin Liu <liuxin350@huawei.com> Signed-off-by:
Weibin Kong <kongweibin2@huawei.com> Signed-off-by:
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Rong Tao authored
Since commit be6bfe36 ("block: inline hot paths of blk_account_io_*()") blk_account_io_*() become inline functions. Signed-off-by:
Rong Tao <rtoax@foxmail.com> Signed-off-by:
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- 20 Sep, 2022 5 commits
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Martin KaFai Lau authored
Daniel Xu says: ==================== This patchset cleans up a few small things: * Delete unused stub * Rename variable to be more descriptive * Fix some `extern` declaration warnings Past discussion: - v2: https://lore.kernel.org/bpf/cover.1663616584.git.dxu@dxuuu.xyz/ Changes since v2: - Remove unused #include's - Move #include <linux/filter.h> to .c ==================== Signed-off-by:
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Daniel Xu authored
We're seeing the following new warnings on netdev/build_32bit and netdev/build_allmodconfig_warn CI jobs: ../net/core/filter.c:8608:1: warning: symbol 'nf_conn_btf_access_lock' was not declared. Should it be static? ../net/core/filter.c:8611:5: warning: symbol 'nfct_bsa' was not declared. Should it be static? Fix by ensuring extern declaration is present while compiling filter.o. Fixes: 864b656f ("bpf: Add support for writing to nf_conn:mark") Signed-off-by:Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/r/2bd2e0283df36d8a4119605878edb1838d144174.1663683114.git.dxu@dxuuu.xyzSigned-off-by:
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Daniel Xu authored
The former name was a little hard to guess. Signed-off-by:
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Daniel Xu authored
This stub was not being used anywhere. Signed-off-by:
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Hou Tao authored
llnode could be NULL if there are new allocations after the checking of c-free_cnt > c->high_watermark in bpf_mem_refill() and before the calling of __llist_del_first() in free_bulk (e.g. a PREEMPT_RT kernel or allocation in NMI context). And it will incur oops as shown below: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT_RT SMP CPU: 39 PID: 373 Comm: irq_work/39 Tainted: G W 6.0.0-rc6-rt9+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:bpf_mem_refill+0x66/0x130 ...... Call Trace: <TASK> irq_work_single+0x24/0x60 irq_work_run_list+0x24/0x30 run_irq_workd+0x18/0x20 smpboot_thread_fn+0x13f/0x2c0 kthread+0x121/0x140 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 </TASK> Simply fixing it by checking whether or not llnode is NULL in free_bulk(). Fixes: 8d5a8011 ("bpf: Batch call_rcu callbacks instead of SLAB_TYPESAFE_BY_RCU.") Signed-off-by:
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- 19 Sep, 2022 1 commit
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Hou Tao authored
Add test result message when test_task_storage_map_stress_lookup() succeeds or is skipped. The test case can be skipped due to the choose of preemption model in kernel config, so export skips in test_maps.c and increase it when needed. The following is the output of test_maps when the test case succeeds or is skipped: test_task_storage_map_stress_lookup:PASS test_maps: OK, 0 SKIPPED test_task_storage_map_stress_lookup SKIP (no CONFIG_PREEMPT) test_maps: OK, 1 SKIPPED Fixes: 73b97bc7 ("selftests/bpf: Test concurrent updates on bpf_task_storage_busy") Signed-off-by:
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- 17 Sep, 2022 1 commit
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Peilin Ye authored
We have btf_type_str(). Use it whenever possible in btf.c, instead of "btf_kind_str[BTF_INFO_KIND(t->info)]". Signed-off-by:
Peilin Ye <peilin.ye@bytedance.com> Link: https://lore.kernel.org/r/20220916202800.31421-1-yepeilin.cs@gmail.comSigned-off-by:
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- 16 Sep, 2022 5 commits
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Xin Liu authored
Legacy BPF map declarations are no longer supported in libbpf v1.0 [0]. Only BTF-defined maps are supported starting from v1.0, so it is time to remove the definition of bpf_map_def in bpf_helpers.h. [0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Acked-by:
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Andrii Nakryiko authored
Add a small tool, veristat, that allows mass-verification of a set of *libbpf-compatible* BPF ELF object files. For each such object file, veristat will attempt to verify each BPF program *individually*. Regardless of success or failure, it parses BPF verifier stats and outputs them in human-readable table format. In the future we can also add CSV and JSON output for more scriptable post-processing, if necessary. veristat allows to specify a set of stats that should be output and ordering between multiple objects and files (e.g., so that one can easily order by total instructions processed, instead of default file name, prog name, verdict, total instructions order). This tool should be useful for validating various BPF verifier changes or even validating different kernel versions for regressions. Here's an example for some of the heaviest selftests/bpf BPF object files: $ sudo ./veristat -s insns,file,prog {pyperf,loop,test_verif_scale,strobemeta,test_cls_redirect,profiler}*.linked3.o File Program Verdict Duration, us Total insns Total states Peak states ------------------------------------ ------------------------------------ ------- ------------ ----------- ------------ ----------- loop3.linked3.o while_true failure 350990 1000001 9663 9663 test_verif_scale3.linked3.o balancer_ingress success 115244 845499 8636 2141 test_verif_scale2.linked3.o balancer_ingress success 77688 773445 3048 788 pyperf600.linked3.o on_event success 2079872 624585 30335 30241 pyperf600_nounroll.linked3.o on_event success 353972 568128 37101 2115 strobemeta.linked3.o on_event success 455230 557149 15915 13537 test_verif_scale1.linked3.o balancer_ingress success 89880 554754 8636 2141 strobemeta_nounroll2.linked3.o on_event success 433906 501725 17087 1912 loop6.linked3.o trace_virtqueue_add_sgs success 282205 398057 8717 919 loop1.linked3.o nested_loops success 125630 361349 5504 5504 pyperf180.linked3.o on_event success 2511740 160398 11470 11446 pyperf100.linked3.o on_event success 744329 87681 6213 6191 test_cls_redirect.linked3.o cls_redirect success 54087 78925 4782 903 strobemeta_subprogs.linked3.o on_event success 57898 65420 1954 403 test_cls_redirect_subprogs.linked3.o cls_redirect success 54522 64965 4619 958 strobemeta_nounroll1.linked3.o on_event success 43313 57240 1757 382 pyperf50.linked3.o on_event success 194355 46378 3263 3241 profiler2.linked3.o tracepoint__syscalls__sys_enter_kill success 23869 43372 1423 542 pyperf_subprogs.linked3.o on_event success 29179 36358 2499 2499 profiler1.linked3.o tracepoint__syscalls__sys_enter_kill success 13052 27036 1946 936 profiler3.linked3.o tracepoint__syscalls__sys_enter_kill success 21023 26016 2186 915 profiler2.linked3.o kprobe__vfs_link success 5255 13896 303 271 profiler1.linked3.o kprobe__vfs_link success 7792 12687 1042 1041 profiler3.linked3.o kprobe__vfs_link success 7332 10601 865 865 profiler2.linked3.o kprobe_ret__do_filp_open success 3417 8900 216 199 profiler2.linked3.o kprobe__vfs_symlink success 3548 8775 203 186 pyperf_global.linked3.o on_event success 10007 7563 520 520 profiler3.linked3.o kprobe_ret__do_filp_open success 4708 6464 532 532 profiler1.linked3.o kprobe_ret__do_filp_open success 3090 6445 508 508 profiler3.linked3.o kprobe__vfs_symlink success 4477 6358 521 521 profiler1.linked3.o kprobe__vfs_symlink success 3381 6347 507 507 profiler2.linked3.o raw_tracepoint__sched_process_exec success 2464 5874 292 189 profiler3.linked3.o raw_tracepoint__sched_process_exec success 2677 4363 397 283 profiler2.linked3.o kprobe__proc_sys_write success 1800 4355 143 138 profiler1.linked3.o raw_tracepoint__sched_process_exec success 1649 4019 333 240 pyperf600_bpf_loop.linked3.o on_event success 2711 3966 306 306 profiler2.linked3.o raw_tracepoint__sched_process_exit success 1234 3138 83 66 profiler3.linked3.o kprobe__proc_sys_write success 1755 2623 223 223 profiler1.linked3.o kprobe__proc_sys_write success 1222 2456 193 193 loop2.linked3.o while_true success 608 1783 57 30 profiler3.linked3.o raw_tracepoint__sched_process_exit success 789 1680 146 146 profiler1.linked3.o raw_tracepoint__sched_process_exit success 592 1526 133 133 strobemeta_bpf_loop.linked3.o on_event success 1015 1512 106 106 loop4.linked3.o combinations success 165 524 18 17 profiler3.linked3.o raw_tracepoint__sched_process_fork success 196 299 25 25 profiler1.linked3.o raw_tracepoint__sched_process_fork success 109 265 19 19 profiler2.linked3.o raw_tracepoint__sched_process_fork success 111 265 19 19 loop5.linked3.o while_true success 47 84 9 9 ------------------------------------ ------------------------------------ ------- ------------ ----------- ------------ ----------- Signed-off-by: -
Andrii Nakryiko authored
Fix SIGSEGV caused by libbpf trying to find attach type in vmlinux BTF for freplace programs. It's wrong to search in vmlinux BTF and libbpf doesn't even mark vmlinux BTF as required for freplace programs. So trying to search anything in obj->vmlinux_btf might cause NULL dereference if nothing else in BPF object requires vmlinux BTF. Instead, error out if freplace (EXT) program doesn't specify attach_prog_fd during at the load time. Fixes: 91abb4a6 ("libbpf: Support attachment of BPF tracing programs to kernel modules") Signed-off-by:
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Andrii Nakryiko authored
Use proper SEC("tc") for test_verif_scale{1,3} programs. It's not a problem for selftests right now because we manually set type programmatically, but not having correct SEC() definitions makes it harded to generically load BPF object files. Signed-off-by: -
Jiri Olsa authored
The dispatcher function is attached/detached to trampoline by dispatcher update function. At the same time it's available as ftrace attachable function. After discussion [1] the proposed solution is to use compiler attributes to alter bpf_dispatcher_##name##_func function: - remove it from being instrumented with __no_instrument_function__ attribute, so ftrace has no track of it - but still generate 5 nop instructions with patchable_function_entry(5) attribute, which are expected by bpf_arch_text_poke used by dispatcher update function Enabling HAVE_DYNAMIC_FTRACE_NO_PATCHABLE option for x86, so __patchable_function_entries functions are not part of ftrace/mcount locations. Adding attributes to bpf_dispatcher_XXX function on x86_64 so it's kept out of ftrace locations and has 5 byte nop generated at entry. These attributes need to be arch specific as pointed out by Ilya Leoshkevic in here [2]. The dispatcher image is generated only for x86_64 arch, so the code can stay as is for other archs. [1] https://lore.kernel.org/bpf/20220722110811.124515-1-jolsa@kernel.org/ [2] https://lore.kernel.org/bpf/969a14281a7791c334d476825863ee449964dd0c.camel@linux.ibm.com/Suggested-by:Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:
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