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2024-06-13bpf: fix UML x86_64 compile failureMaciej Żenczykowski
pcpu_hot (defined in arch/x86) is not available on user mode linux (ARCH=um) Cc: Andrii Nakryiko <andrii@kernel.org> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Fixes: 1ae6921009e5 ("bpf: inline bpf_get_smp_processor_id() helper") Signed-off-by: Maciej Żenczykowski <maze@google.com> Link: https://lore.kernel.org/r/20240613173146.2524647-1-maze@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-06-13bpf: Fix bpf_dynptr documentation commentsDaniel Xu
The function argument names were changed but the doc comment was not. Fix htmldocs build warning by updating doc comments. Fixes: cce4c40b9606 ("bpf: treewide: Align kfunc signatures to prog point-of-view") Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/r/d0b0eb05f91e12e5795966153b11998d3fc1d433.1718295425.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-06-13bpf: Reduce stack consumption in check_stack_write_fixed_offDaniel Borkmann
The fake_reg moved into env->fake_reg given it consumes a lot of stack space (120 bytes). Migrate the fake_reg in check_stack_write_fixed_off() as well now that we have it. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20240613115310.25383-2-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-06-13bpf: Fix reg_set_min_max corruption of fake_regDaniel Borkmann
Juan reported that after doing some changes to buzzer [0] and implementing a new fuzzing strategy guided by coverage, they noticed the following in one of the probes: [...] 13: (79) r6 = *(u64 *)(r0 +0) ; R0=map_value(ks=4,vs=8) R6_w=scalar() 14: (b7) r0 = 0 ; R0_w=0 15: (b4) w0 = -1 ; R0_w=0xffffffff 16: (74) w0 >>= 1 ; R0_w=0x7fffffff 17: (5c) w6 &= w0 ; R0_w=0x7fffffff R6_w=scalar(smin=smin32=0,smax=umax=umax32=0x7fffffff,var_off=(0x0; 0x7fffffff)) 18: (44) w6 |= 2 ; R6_w=scalar(smin=umin=smin32=umin32=2,smax=umax=umax32=0x7fffffff,var_off=(0x2; 0x7ffffffd)) 19: (56) if w6 != 0x7ffffffd goto pc+1 REG INVARIANTS VIOLATION (true_reg2): range bounds violation u64=[0x7fffffff, 0x7ffffffd] s64=[0x7fffffff, 0x7ffffffd] u32=[0x7fffffff, 0x7ffffffd] s32=[0x7fffffff, 0x7ffffffd] var_off=(0x7fffffff, 0x0) REG INVARIANTS VIOLATION (false_reg1): range bounds violation u64=[0x7fffffff, 0x7ffffffd] s64=[0x7fffffff, 0x7ffffffd] u32=[0x7fffffff, 0x7ffffffd] s32=[0x7fffffff, 0x7ffffffd] var_off=(0x7fffffff, 0x0) REG INVARIANTS VIOLATION (false_reg2): const tnum out of sync with range bounds u64=[0x0, 0xffffffffffffffff] s64=[0x8000000000000000, 0x7fffffffffffffff] u32=[0x0, 0xffffffff] s32=[0x80000000, 0x7fffffff] var_off=(0x7fffffff, 0x0) 19: R6_w=0x7fffffff 20: (95) exit from 19 to 21: R0=0x7fffffff R6=scalar(smin=umin=smin32=umin32=2,smax=umax=smax32=umax32=0x7ffffffe,var_off=(0x2; 0x7ffffffd)) R7=map_ptr(ks=4,vs=8) R9=ctx() R10=fp0 fp-24=map_ptr(ks=4,vs=8) fp-40=mmmmmmmm 21: R0=0x7fffffff R6=scalar(smin=umin=smin32=umin32=2,smax=umax=smax32=umax32=0x7ffffffe,var_off=(0x2; 0x7ffffffd)) R7=map_ptr(ks=4,vs=8) R9=ctx() R10=fp0 fp-24=map_ptr(ks=4,vs=8) fp-40=mmmmmmmm 21: (14) w6 -= 2147483632 ; R6_w=scalar(smin=umin=umin32=2,smax=umax=0xffffffff,smin32=0x80000012,smax32=14,var_off=(0x2; 0xfffffffd)) 22: (76) if w6 s>= 0xe goto pc+1 ; R6_w=scalar(smin=umin=umin32=2,smax=umax=0xffffffff,smin32=0x80000012,smax32=13,var_off=(0x2; 0xfffffffd)) 23: (95) exit from 22 to 24: R0=0x7fffffff R6_w=14 R7=map_ptr(ks=4,vs=8) R9=ctx() R10=fp0 fp-24=map_ptr(ks=4,vs=8) fp-40=mmmmmmmm 24: R0=0x7fffffff R6_w=14 R7=map_ptr(ks=4,vs=8) R9=ctx() R10=fp0 fp-24=map_ptr(ks=4,vs=8) fp-40=mmmmmmmm 24: (14) w6 -= 14 ; R6_w=0 [...] What can be seen here is a register invariant violation on line 19. After the binary-or in line 18, the verifier knows that bit 2 is set but knows nothing about the rest of the content which was loaded from a map value, meaning, range is [2,0x7fffffff] with var_off=(0x2; 0x7ffffffd). When in line 19 the verifier analyzes the branch, it splits the register states in reg_set_min_max() into the registers of the true branch (true_reg1, true_reg2) and the registers of the false branch (false_reg1, false_reg2). Since the test is w6 != 0x7ffffffd, the src_reg is a known constant. Internally, the verifier creates a "fake" register initialized as scalar to the value of 0x7ffffffd, and then passes it onto reg_set_min_max(). Now, for line 19, it is mathematically impossible to take the false branch of this program, yet the verifier analyzes it. It is impossible because the second bit of r6 will be set due to the prior or operation and the constant in the condition has that bit unset (hex(fd) == binary(1111 1101). When the verifier first analyzes the false / fall-through branch, it will compute an intersection between the var_off of r6 and of the constant. This is because the verifier creates a "fake" register initialized to the value of the constant. The intersection result later refines both registers in regs_refine_cond_op(): [...] t = tnum_intersect(tnum_subreg(reg1->var_off), tnum_subreg(reg2->var_off)); reg1->var_off = tnum_with_subreg(reg1->var_off, t); reg2->var_off = tnum_with_subreg(reg2->var_off, t); [...] Since the verifier is analyzing the false branch of the conditional jump, reg1 is equal to false_reg1 and reg2 is equal to false_reg2, i.e. the reg2 is the "fake" register that was meant to hold a constant value. The resulting var_off of the intersection says that both registers now hold a known value of var_off=(0x7fffffff, 0x0) or in other words: this operation manages to make the verifier think that the "constant" value that was passed in the jump operation now holds a different value. Normally this would not be an issue since it should not influence the true branch, however, false_reg2 and true_reg2 are pointers to the same "fake" register. Meaning, the false branch can influence the results of the true branch. In line 24, the verifier assumes R6_w=0, but the actual runtime value in this case is 1. The fix is simply not passing in the same "fake" register location as inputs to reg_set_min_max(), but instead making a copy. Moving the fake_reg into the env also reduces stack consumption by 120 bytes. With this, the verifier successfully rejects invalid accesses from the test program. [0] https://github.com/google/buzzer Fixes: 67420501e868 ("bpf: generalize reg_set_min_max() to handle non-const register comparisons") Reported-by: Juan José López Jaimez <jjlopezjaimez@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/r/20240613115310.25383-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-06-13locking: Remove superfluous sentinel element from kern_lockdep_tableJoel Granados
This commit is part of a greater effort to remove all empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Signed-off-by: Joel Granados <j.granados@samsung.com>
2024-06-12bpf: treewide: Align kfunc signatures to prog point-of-viewDaniel Xu
Previously, kfunc declarations in bpf_kfuncs.h (and others) used "user facing" types for kfuncs prototypes while the actual kfunc definitions used "kernel facing" types. More specifically: bpf_dynptr vs bpf_dynptr_kern, __sk_buff vs sk_buff, and xdp_md vs xdp_buff. It wasn't an issue before, as the verifier allows aliased types. However, since we are now generating kfunc prototypes in vmlinux.h (in addition to keeping bpf_kfuncs.h around), this conflict creates compilation errors. Fix this conflict by using "user facing" types in kfunc definitions. This results in more casts, but otherwise has no additional runtime cost. Note, similar to 5b268d1ebcdc ("bpf: Have bpf_rdonly_cast() take a const pointer"), we also make kfuncs take const arguments where appropriate in order to make the kfunc more permissive. Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/r/b58346a63a0e66bc9b7504da751b526b0b189a67.1718207789.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-06-12bpf: verifier: Relax caller requirements for kfunc projection type argsDaniel Xu
Currently, if a kfunc accepts a projection type as an argument (eg struct __sk_buff *), the caller must exactly provide exactly the same type with provable provenance. However in practice, kfuncs that accept projection types _must_ cast to the underlying type before use b/c projection type layouts are completely made up. Thus, it is ok to relax the verifier rules around implicit conversions. We will use this functionality in the next commit when we align kfuncs to user-facing types. Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/r/e2c025cb09ccfd4af1ec9e18284dc3cecff7514d.1718207789.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-06-12bpf: Make bpf_session_cookie() kfunc return long *Daniel Xu
We will soon be generating kfunc prototypes from BTF. As part of that, we need to align the manual signatures in bpf_kfuncs.h with the actual kfunc definitions. There is currently a conflicting signature for bpf_session_cookie() w.r.t. return type. The original intent was to return long * and not __u64 *. You can see evidence of that intent in a3a5113393cc ("selftests/bpf: Add kprobe session cookie test"). Fix conflict by changing kfunc definition. Fixes: 5c919acef851 ("bpf: Add support for kprobe session cookie") Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/r/7043e1c251ab33151d6e3830f8ea1902ed2604ac.1718207789.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-06-12tracing/kprobe: Remove cleanup code unrelated to selftestMasami Hiramatsu (Google)
This cleanup all kprobe events code is not related to the selftest itself, and it can fail by the reason unrelated to this test. If the test is successful, the generated events are cleaned up. And if not, we cannot guarantee that the kprobe events will work correctly. So, anyway, there is no need to clean it up. Link: https://lore.kernel.org/all/171811265627.85078.16897867213512435822.stgit@devnote2/ Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-12tracing/kprobe: Integrate test warnings into WARN_ONCEMasami Hiramatsu (Google)
Cleanup the redundant WARN_ON_ONCE(cond) + pr_warn(msg) into WARN_ONCE(cond, msg). Also add some WARN_ONCE() for hitcount check. These WARN_ONCE() errors makes it easy to handle errors from ktest. Link: https://lore.kernel.org/all/171811264685.85078.8068819097047430463.stgit@devnote2/ Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-12uprobe: Add uretprobe syscall to speed up return probeJiri Olsa
Adding uretprobe syscall instead of trap to speed up return probe. At the moment the uretprobe setup/path is: - install entry uprobe - when the uprobe is hit, it overwrites probed function's return address on stack with address of the trampoline that contains breakpoint instruction - the breakpoint trap code handles the uretprobe consumers execution and jumps back to original return address This patch replaces the above trampoline's breakpoint instruction with new ureprobe syscall call. This syscall does exactly the same job as the trap with some more extra work: - syscall trampoline must save original value for rax/r11/rcx registers on stack - rax is set to syscall number and r11/rcx are changed and used by syscall instruction - the syscall code reads the original values of those registers and restore those values in task's pt_regs area - only caller from trampoline exposed in '[uprobes]' is allowed, the process will receive SIGILL signal otherwise Even with some extra work, using the uretprobes syscall shows speed improvement (compared to using standard breakpoint): On Intel (11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz) current: uretprobe-nop : 1.498 ± 0.000M/s uretprobe-push : 1.448 ± 0.001M/s uretprobe-ret : 0.816 ± 0.001M/s with the fix: uretprobe-nop : 1.969 ± 0.002M/s < 31% speed up uretprobe-push : 1.910 ± 0.000M/s < 31% speed up uretprobe-ret : 0.934 ± 0.000M/s < 14% speed up On Amd (AMD Ryzen 7 5700U) current: uretprobe-nop : 0.778 ± 0.001M/s uretprobe-push : 0.744 ± 0.001M/s uretprobe-ret : 0.540 ± 0.001M/s with the fix: uretprobe-nop : 0.860 ± 0.001M/s < 10% speed up uretprobe-push : 0.818 ± 0.001M/s < 10% speed up uretprobe-ret : 0.578 ± 0.000M/s < 7% speed up The performance test spawns a thread that runs loop which triggers uprobe with attached bpf program that increments the counter that gets printed in results above. The uprobe (and uretprobe) kind is determined by which instruction is being patched with breakpoint instruction. That's also important for uretprobes, because uprobe is installed for each uretprobe. The performance test is part of bpf selftests: tools/testing/selftests/bpf/run_bench_uprobes.sh Note at the moment uretprobe syscall is supported only for native 64-bit process, compat process still uses standard breakpoint. Note that when shadow stack is enabled the uretprobe syscall returns via iret, which is slower than return via sysret, but won't cause the shadow stack violation. Link: https://lore.kernel.org/all/20240611112158.40795-4-jolsa@kernel.org/ Suggested-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-06-12uprobe: Wire up uretprobe system callJiri Olsa
Wiring up uretprobe system call, which comes in following changes. We need to do the wiring before, because the uretprobe implementation needs the syscall number. Note at the moment uretprobe syscall is supported only for native 64-bit process. Link: https://lore.kernel.org/all/20240611112158.40795-3-jolsa@kernel.org/ Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-06-12tracing: Build event generation tests only as modulesMasami Hiramatsu (Google)
The kprobes and synth event generation test modules add events and lock (get a reference) those event file reference in module init function, and unlock and delete it in module exit function. This is because those are designed for playing as modules. If we make those modules as built-in, those events are left locked in the kernel, and never be removed. This causes kprobe event self-test failure as below. [ 97.349708] ------------[ cut here ]------------ [ 97.353453] WARNING: CPU: 3 PID: 1 at kernel/trace/trace_kprobe.c:2133 kprobe_trace_self_tests_init+0x3f1/0x480 [ 97.357106] Modules linked in: [ 97.358488] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 6.9.0-g699646734ab5-dirty #14 [ 97.361556] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [ 97.363880] RIP: 0010:kprobe_trace_self_tests_init+0x3f1/0x480 [ 97.365538] Code: a8 24 08 82 e9 ae fd ff ff 90 0f 0b 90 48 c7 c7 e5 aa 0b 82 e9 ee fc ff ff 90 0f 0b 90 48 c7 c7 2d 61 06 82 e9 8e fd ff ff 90 <0f> 0b 90 48 c7 c7 33 0b 0c 82 89 c6 e8 6e 03 1f ff 41 ff c7 e9 90 [ 97.370429] RSP: 0000:ffffc90000013b50 EFLAGS: 00010286 [ 97.371852] RAX: 00000000fffffff0 RBX: ffff888005919c00 RCX: 0000000000000000 [ 97.373829] RDX: ffff888003f40000 RSI: ffffffff8236a598 RDI: ffff888003f40a68 [ 97.375715] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 [ 97.377675] R10: ffffffff811c9ae5 R11: ffffffff8120c4e0 R12: 0000000000000000 [ 97.379591] R13: 0000000000000001 R14: 0000000000000015 R15: 0000000000000000 [ 97.381536] FS: 0000000000000000(0000) GS:ffff88807dcc0000(0000) knlGS:0000000000000000 [ 97.383813] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 97.385449] CR2: 0000000000000000 CR3: 0000000002244000 CR4: 00000000000006b0 [ 97.387347] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 97.389277] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 97.391196] Call Trace: [ 97.391967] <TASK> [ 97.392647] ? __warn+0xcc/0x180 [ 97.393640] ? kprobe_trace_self_tests_init+0x3f1/0x480 [ 97.395181] ? report_bug+0xbd/0x150 [ 97.396234] ? handle_bug+0x3e/0x60 [ 97.397311] ? exc_invalid_op+0x1a/0x50 [ 97.398434] ? asm_exc_invalid_op+0x1a/0x20 [ 97.399652] ? trace_kprobe_is_busy+0x20/0x20 [ 97.400904] ? tracing_reset_all_online_cpus+0x15/0x90 [ 97.402304] ? kprobe_trace_self_tests_init+0x3f1/0x480 [ 97.403773] ? init_kprobe_trace+0x50/0x50 [ 97.404972] do_one_initcall+0x112/0x240 [ 97.406113] do_initcall_level+0x95/0xb0 [ 97.407286] ? kernel_init+0x1a/0x1a0 [ 97.408401] do_initcalls+0x3f/0x70 [ 97.409452] kernel_init_freeable+0x16f/0x1e0 [ 97.410662] ? rest_init+0x1f0/0x1f0 [ 97.411738] kernel_init+0x1a/0x1a0 [ 97.412788] ret_from_fork+0x39/0x50 [ 97.413817] ? rest_init+0x1f0/0x1f0 [ 97.414844] ret_from_fork_asm+0x11/0x20 [ 97.416285] </TASK> [ 97.417134] irq event stamp: 13437323 [ 97.418376] hardirqs last enabled at (13437337): [<ffffffff8110bc0c>] console_unlock+0x11c/0x150 [ 97.421285] hardirqs last disabled at (13437370): [<ffffffff8110bbf1>] console_unlock+0x101/0x150 [ 97.423838] softirqs last enabled at (13437366): [<ffffffff8108e17f>] handle_softirqs+0x23f/0x2a0 [ 97.426450] softirqs last disabled at (13437393): [<ffffffff8108e346>] __irq_exit_rcu+0x66/0xd0 [ 97.428850] ---[ end trace 0000000000000000 ]--- And also, since we can not cleanup dynamic_event file, ftracetest are failed too. To avoid these issues, build these tests only as modules. Link: https://lore.kernel.org/all/171811263754.85078.5877446624311852525.stgit@devnote2/ Fixes: 9fe41efaca08 ("tracing: Add synth event generation test module") Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module") Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-11ftrace: Add missing kerneldoc parameters to unregister_ftrace_direct()Marilene A Garcia
Add the description to the parameters addr and free_filters of the function unregister_ftrace_direct(). Link: https://lore.kernel.org/linux-trace-kernel/20240606132520.1397567-1-marilene.agarcia@gmail.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Javier Carrasco <javier.carrasco.cruz@gmail.com> Signed-off-by: Marilene A Garcia <marilene.agarcia@gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-11function_graph: Everyone uses HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, remove itSteven Rostedt (Google)
All architectures that implement function graph also implements HAVE_FUNCTION_GRAPH_RET_ADDR_PTR. Remove it, as it is no longer a differentiator. Link: https://lore.kernel.org/linux-trace-kernel/20240611031737.982047614@goodmis.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Guo Ren <guoren@kernel.org> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-11function_graph: Fix up ftrace_graph_ret_addr()Steven Rostedt (Google)
Yang Li sent a patch to fix the kerneldoc of ftrace_graph_ret_addr(). While reviewing it, I realized that the comments in the entire function header needed a rewrite. When doing that, I realized that @idx parameter was being ignored. Every time this was called by the unwinder, it would start the loop at the top of the shadow stack and look for the matching stack pointer. When it found it, it would return it. When the unwinder asked for the next function, it would search from the beginning again. In reality, it should start from where it left off. That was the reason for the @idx parameter in the first place. The first time the unwinder calls this function, the @idx pointer would contain zero. That would mean to start from the top of the stack. The function was supposed to update the @idx with the index where it found the return address, so that the next time the unwinder calls this function it doesn't have to search through the previous addresses it found (making it O(n^2)!). This speeds up the unwinder's use of ftrace_graph_ret_addr() by an order of magnitude. Link: https://lore.kernel.org/linux-trace-kernel/20240610181746.656e3759@gandalf.local.home/ Link: https://lore.kernel.org/linux-trace-kernel/20240611031737.821995106@goodmis.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Guo Ren <guoren@kernel.org> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Reported-by: Yang Li <yang.lee@linux.alibaba.com> Fixes: 7aa1eaef9f428 ("function_graph: Allow multiple users to attach to function graph") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-11jump_label: Simplify and clarify static_key_fast_inc_cpus_locked()Thomas Gleixner
Make the code more obvious and add proper comments to avoid future head scratching. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20240610124406.548322963@linutronix.de
2024-06-11jump_label: Clarify condition in static_key_fast_inc_not_disabled()Thomas Gleixner
The second part of if (v <= 0 || (v + 1) < 0) is not immediately obvious that it acts as overflow protection. Check explicitely for v == INT_MAX instead and add a proper comment how this is used at the call sites. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20240610124406.484973160@linutronix.de
2024-06-11jump_label: Fix concurrency issues in static_key_slow_dec()Thomas Gleixner
The commit which tried to fix the concurrency issues of concurrent static_key_slow_inc() failed to fix the equivalent issues vs. static_key_slow_dec(): CPU0 CPU1 static_key_slow_dec() static_key_slow_try_dec() key->enabled == 1 val = atomic_fetch_add_unless(&key->enabled, -1, 1); if (val == 1) return false; jump_label_lock(); if (atomic_dec_and_test(&key->enabled)) { --> key->enabled == 0 __jump_label_update() static_key_slow_dec() static_key_slow_try_dec() key->enabled == 0 val = atomic_fetch_add_unless(&key->enabled, -1, 1); --> key->enabled == -1 <- FAIL There is another bug in that code, when there is a concurrent static_key_slow_inc() which enables the key as that sets key->enabled to -1 so on the other CPU val = atomic_fetch_add_unless(&key->enabled, -1, 1); will succeed and decrement to -2, which is invalid. Cure all of this by replacing the atomic_fetch_add_unless() with a atomic_try_cmpxchg() loop similar to static_key_fast_inc_not_disabled(). [peterz: add WARN_ON_ONCE for the -1 race] Fixes: 4c5ea0a9cd02 ("locking/static_key: Fix concurrent static_key_slow_inc()") Reported-by: Yue Sun <samsun1006219@gmail.com> Reported-by: Xingwei Lee <xrivendell7@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20240610124406.422897838@linutronix.de
2024-06-10Merge tag 'for-netdev' of ↵Jakub Kicinski
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Daniel Borkmann says: ==================== pull-request: bpf-next 2024-06-06 We've added 54 non-merge commits during the last 10 day(s) which contain a total of 50 files changed, 1887 insertions(+), 527 deletions(-). The main changes are: 1) Add a user space notification mechanism via epoll when a struct_ops object is getting detached/unregistered, from Kui-Feng Lee. 2) Big batch of BPF selftest refactoring for sockmap and BPF congctl tests, from Geliang Tang. 3) Add BTF field (type and string fields, right now) iterator support to libbpf instead of using existing callback-based approaches, from Andrii Nakryiko. 4) Extend BPF selftests for the latter with a new btf_field_iter selftest, from Alan Maguire. 5) Add new kfuncs for a generic, open-coded bits iterator, from Yafang Shao. 6) Fix BPF selftests' kallsyms_find() helper under kernels configured with CONFIG_LTO_CLANG_THIN, from Yonghong Song. 7) Remove a bunch of unused structs in BPF selftests, from David Alan Gilbert. 8) Convert test_sockmap section names into names understood by libbpf so it can deduce program type and attach type, from Jakub Sitnicki. 9) Extend libbpf with the ability to configure log verbosity via LIBBPF_LOG_LEVEL environment variable, from Mykyta Yatsenko. 10) Fix BPF selftests with regards to bpf_cookie and find_vma flakiness in nested VMs, from Song Liu. 11) Extend riscv32/64 JITs to introduce shift/add helpers to generate Zba optimization, from Xiao Wang. 12) Enable BPF programs to declare arrays and struct fields with kptr, bpf_rb_root, and bpf_list_head, from Kui-Feng Lee. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (54 commits) selftests/bpf: Drop useless arguments of do_test in bpf_tcp_ca selftests/bpf: Use start_test in test_dctcp in bpf_tcp_ca selftests/bpf: Use start_test in test_dctcp_fallback in bpf_tcp_ca selftests/bpf: Add start_test helper in bpf_tcp_ca selftests/bpf: Use connect_to_fd_opts in do_test in bpf_tcp_ca libbpf: Auto-attach struct_ops BPF maps in BPF skeleton selftests/bpf: Add btf_field_iter selftests selftests/bpf: Fix send_signal test with nested CONFIG_PARAVIRT libbpf: Remove callback-based type/string BTF field visitor helpers bpftool: Use BTF field iterator in btfgen libbpf: Make use of BTF field iterator in BTF handling code libbpf: Make use of BTF field iterator in BPF linker code libbpf: Add BTF field iterator selftests/bpf: Ignore .llvm.<hash> suffix in kallsyms_find() selftests/bpf: Fix bpf_cookie and find_vma in nested VM selftests/bpf: Test global bpf_list_head arrays. selftests/bpf: Test global bpf_rb_root arrays and fields in nested struct types. selftests/bpf: Test kptr arrays and kptrs in nested struct fields. bpf: limit the number of levels of a nested struct type. bpf: look into the types of the fields of a struct type recursively. ... ==================== Link: https://lore.kernel.org/r/20240606223146.23020-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-06-10function_graph: Make fgraph_update_pid_func() a stub for !DYNAMIC_FTRACESteven Rostedt (Google)
When CONFIG_DYNAMIC_FTRACE is not set, the function fgraph_update_pid_func() doesn't do anything. Currently, most of its logic is within a "#ifdef CONFIG_DYNAMIC_FTRACE" block, but its variables were declared outside that, and when DYNAMIC_FTRACE is not set, it produces unused variable warnings. Instead, just place it (and the helper function fgraph_pid_func()) within the #ifdef block and have the header file use a empty stub function for when DYNAMIC_FTRACE is not defined. Link: https://lore.kernel.org/linux-trace-kernel/20240607094833.6a787d73@rorschach.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202406071806.BRjaC5FF-lkp@intel.com/ Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-10workqueue: replace call_rcu by kfree_rcu for simple kmem_cache_free callbackJulia Lawall
Since SLOB was removed, it is not necessary to use call_rcu when the callback only performs kmem_cache_free. Use kfree_rcu() directly. The changes were done using the following Coccinelle semantic patch. This semantic patch is designed to ignore cases where the callback function is used in another way. // <smpl> @r@ expression e; local idexpression e2; identifier cb,f; position p; @@ ( call_rcu(...,e2) | call_rcu(&e->f,cb@p) ) @r1@ type T; identifier x,r.cb; @@ cb(...) { ( kmem_cache_free(...); | T x = ...; kmem_cache_free(...,x); | T x; x = ...; kmem_cache_free(...,x); ) } @s depends on r1@ position p != r.p; identifier r.cb; @@ cb@p @script:ocaml@ cb << r.cb; p << s.p; @@ Printf.eprintf "Other use of %s at %s:%d\n" cb (List.hd p).file (List.hd p).line @depends on r1 && !s@ expression e; identifier r.cb,f; position r.p; @@ - call_rcu(&e->f,cb@p) + kfree_rcu(e,f) @r1a depends on !s@ type T; identifier x,r.cb; @@ - cb(...) { ( - kmem_cache_free(...); | - T x = ...; - kmem_cache_free(...,x); | - T x; - x = ...; - kmem_cache_free(...,x); ) - } // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-10tick/nohz_full: Don't abuse smp_call_function_single() in tick_setup_device()Oleg Nesterov
After the recent commit 5097cbcb38e6 ("sched/isolation: Prevent boot crash when the boot CPU is nohz_full") the kernel no longer crashes, but there is another problem. In this case tick_setup_device() calls tick_take_do_timer_from_boot() to update tick_do_timer_cpu and this triggers the WARN_ON_ONCE(irqs_disabled) in smp_call_function_single(). Kill tick_take_do_timer_from_boot() and just use WRITE_ONCE(), the new comment explains why this is safe (thanks Thomas!). Fixes: 08ae95f4fd3b ("nohz_full: Allow the boot CPU to be nohz_full") Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240528122019.GA28794@redhat.com Link: https://lore.kernel.org/all/20240522151742.GA10400@redhat.com
2024-06-08Merge tag 'perf-urgent-2024-06-08' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf event fix from Ingo Molnar: "Fix race between perf_event_free_task() and perf_event_release_kernel() that can result in missed wakeups and hung tasks" * tag 'perf-urgent-2024-06-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/core: Fix missing wakeup when waiting for context reference
2024-06-07workqueue: Clean code in alloc_and_link_pwqs()Wenchao Hao
wq->flags would not change, so it's not necessary to check if WQ_BH is set in loop for_each_possible_cpu(), move define and set of pools out of loop to simpliy the code. Signed-off-by: Wenchao Hao <haowenchao22@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-06function_graph: Rename BYTE_NUMBER to CHAR_NUMBER in selftestsSteven Rostedt (Google)
The function_graph selftests checks various size variables to pass from the entry of the function to the exit. It tests 1, 2, 4 and 8 byte words. The 1 byte macro was called BYTE_NUMBER but that is used in the sh architecture: arch/sh/include/asm/bitops-op32.h Just rename the macro to CHAR_NUMBER. Link: https://lore.kernel.org/linux-trace-kernel/20240606081846.4cb82dc4@gandalf.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Fixes: 47c3c70aa3697 ("function_graph: Add selftest for passing local variables") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202406061744.rZDXfRrG-lkp@intel.com/ Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06fgraph: Remove some unused functionsJiapeng Chong
These functions are defined in the fgraph.c file, but not called elsewhere, so delete these unused functions. kernel/trace/fgraph.c:273:1: warning: unused function 'set_bitmap_bits'. kernel/trace/fgraph.c:259:19: warning: unused function 'get_fgraph_type'. Link: https://lore.kernel.org/linux-trace-kernel/20240606021053.27783-1-jiapeng.chong@linux.alibaba.com Reported-by: Abaci Robot <abaci@linux.alibaba.com> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9289 Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06ftrace: Hide one more entry in stack trace when ftrace_pid is enabledTatsuya S
On setting set_ftrace_pid, a extra entry generated by ftrace_pid_func() is shown on stack trace(CONFIG_UNWINDER_FRAME_POINTER=y). [004] ..... 68.459382: <stack trace> => 0xffffffffa00090af => ksys_read => __x64_sys_read => x64_sys_call => do_syscall_64 => entry_SYSCALL_64_after_hwframe To resolve this issue, increment skip count in function_stack_trace_call() if pids are set. Link: https://lore.kernel.org/linux-trace-kernel/20240528032604.6813-3-tatsuya.s2862@gmail.com Signed-off-by: Tatsuya S <tatsuya.s2862@gmail.com> [ Rebased to current tree ] Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06function_graph: Do not update pid func if CONFIG_DYNAMIC_FTRACE not enabledSteven Rostedt (Google)
The ftrace subops is only defined if CONFIG_DYNAMIC_FTRACE is enabled. If it is not, function tracing is extremely limited, and the subops in the ftrace_ops structure is not defined (and will fail to compile). If DYNAMIC_FTRACE is not enabled, then function graph filtering will not work (as it shouldn't). Link: https://lore.kernel.org/linux-trace-kernel/20240605202709.096020676@goodmis.org Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: df3ec5da6a1e7 ("function_graph: Add pid tracing back to function graph tracer") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202406051855.9VIYXbTB-lkp@intel.com/ Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06function_graph: Make fgraph_do_direct static key staticSteven Rostedt (Google)
The static branch key "fgraph_do_direct" was not declared static but is only used in one file. Change it to a static variable. Link: https://lore.kernel.org/linux-trace-kernel/20240605202708.936515302@goodmis.org Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: cc60ee813b503 ("function_graph: Use static_call and branch to optimize entry function") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202406051711.dS1sQZ9n-lkp@intel.com/ Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06ftrace: Fix prototypes for ftrace_startup/shutdown_subops()Steven Rostedt (Google)
The ftrace_startup_subops() was in the wrong header, and both functions were not defined on !CONFIG_DYNAMIC_FTRACE. Link: https://lore.kernel.org/linux-trace-kernel/20240605202708.773583114@goodmis.org Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: 5fccc7552ccbc ("ftrace: Add subops logic to allow one ops to manage many") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202406051524.a12JqLqx-lkp@intel.com/ Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06ftrace: Assign RCU list variable with rcu_assign_ptr()Steven Rostedt (Google)
Use rcu_assign_ptr() to assign the list pointer as it is marked as RCU, and this quiets the sparse warning: kernel/trace/ftrace.c:313:23: warning: incorrect type in assignment (different address spaces) kernel/trace/ftrace.c:313:23: expected struct ftrace_ops [noderef] __rcu * kernel/trace/ftrace.c:313:23: got struct ftrace_ops * Link: https://lore.kernel.org/linux-trace-kernel/20240605202708.613471310@goodmis.org Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06ftrace: Assign ftrace_list_end to ftrace_ops_list type cast to RCUSteven Rostedt (Google)
Use a type cast to convert ftrace_list_end to RCU when assigning ftrace_ops_list. This will quiet the sparse warning: kernel/trace/ftrace.c:125:59: warning: incorrect type in initializer (different address spaces) kernel/trace/ftrace.c:125:59: expected struct ftrace_ops [noderef] __rcu *[addressable] [toplevel] ftrace_ops_list kernel/trace/ftrace.c:125:59: got struct ftrace_ops * Link: https://lore.kernel.org/linux-trace-kernel/20240605202708.450784356@goodmis.org Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06ftrace: Add comments to ftrace_hash_move() and friendsSteven Rostedt (Google)
Describe what ftrace_hash_move() does and add some more comments to some other functions to make it easier to understand. Link: https://lore.kernel.org/linux-trace-kernel/20240605180409.179520305@goodmis.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06ftrace: Convert "inc" parameter to bool in ftrace_hash_rec_update_modify()Steven Rostedt (Google)
The parameter "inc" in the function ftrace_hash_rec_update_modify() is boolean. Change it to be such. Also add documentation to what the function does. Link: https://lore.kernel.org/linux-trace-kernel/20240605180409.021080462@goodmis.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06ftrace: Add comments to ftrace_hash_rec_disable/enable()Steven Rostedt (Google)
Add comments to describe what the functions ftrace_hash_rec_disable() and ftrace_hash_rec_enable() do. Also change the passing of the "inc" variable to __ftrace_hash_rec_update() to a boolean value as that is what it is supposed to take. Link: https://lore.kernel.org/linux-trace-kernel/20240605180408.857333430@goodmis.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06ftrace: Remove "filter_hash" parameter from __ftrace_hash_rec_update()Steven Rostedt (Google)
While adding comments to the function __ftrace_hash_rec_update() and trying to describe in detail what the parameter for "filter_hash" does, I realized that it basically does exactly the same thing (but differently) if it is set or not! If it is set, the idea was the ops->filter_hash was being updated, and the code should focus on the functions that are in the ops->filter_hash and add them. But it still had to pay attention to the functions in the ops->notrace_hash, to ignore them. If it was cleared, it focused on the ops->notrace_hash, and would add functions that were not in the ops->notrace_hash but would still keep functions in the "ops->filter_hash". Basically doing the same thing. In reality, the __ftrace_hash_rec_update() only needs to either remove the functions associated to the give ops (if "inc" is set) or remove them (if "inc" is cleared). It has to pay attention to both the filter_hash and notrace_hash regardless. Remove the "filter_hash" parameter from __filter_hash_rec_update() and comment the function for what it really is doing. Link: https://lore.kernel.org/linux-trace-kernel/20240605180408.691995506@goodmis.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR. No conflicts. Adjacent changes: drivers/net/ethernet/pensando/ionic/ionic_txrx.c d9c04209990b ("ionic: Mark error paths in the data path as unlikely") 491aee894a08 ("ionic: fix kernel panic in XDP_TX action") net/ipv6/ip6_fib.c b4cb4a1391dc ("net: use unrcu_pointer() helper") b01e1c030770 ("ipv6: fix possible race in __fib6_drop_pcpu_from()") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-06-06rcu/tasks: Fix stale task snaphot for Tasks TraceFrederic Weisbecker
When RCU-TASKS-TRACE pre-gp takes a snapshot of the current task running on all online CPUs, no explicit ordering synchronizes properly with a context switch. This lack of ordering can permit the new task to miss pre-grace-period update-side accesses. The following diagram, courtesy of Paul, shows the possible bad scenario: CPU 0 CPU 1 ----- ----- // Pre-GP update side access WRITE_ONCE(*X, 1); smp_mb(); r0 = rq->curr; RCU_INIT_POINTER(rq->curr, TASK_B) spin_unlock(rq) rcu_read_lock_trace() r1 = X; /* ignore TASK_B */ Either r0==TASK_B or r1==1 is needed but neither is guaranteed. One possible solution to solve this is to wait for an RCU grace period at the beginning of the RCU-tasks-trace grace period before taking the current tasks snaphot. However this would introduce large additional latencies to RCU-tasks-trace grace periods. Another solution is to lock the target runqueue while taking the current task snapshot. This ensures that the update side sees the latest context switch and subsequent context switches will see the pre-grace-period update side accesses. This commit therefore adds runqueue locking to cpu_curr_snapshot(). Fixes: e386b6725798 ("rcu-tasks: Eliminate RCU Tasks Trace IPIs to online CPUs") Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2024-06-06rcutorture: Add missing MODULE_DESCRIPTION() macrosJeff Johnson
Fix the following 'make W=1' warnings: WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/rcutorture.o WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/rcuscale.o WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/rcu/refscale.o Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2024-06-06rcutorture: Fix rcu_torture_fwd_cb_cr() data racePaul E. McKenney
On powerpc systems, spinlock acquisition does not order prior stores against later loads. This means that this statement: rfcp->rfc_next = NULL; Can be reordered to follow this statement: WRITE_ONCE(*rfcpp, rfcp); Which is then a data race with rcu_torture_fwd_prog_cr(), specifically, this statement: rfcpn = READ_ONCE(rfcp->rfc_next) KCSAN located this data race, which represents a real failure on powerpc. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Acked-by: Marco Elver <elver@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: <kasan-dev@googlegroups.com>
2024-06-06kcsan: Add missing MODULE_DESCRIPTION() macroJeff Johnson
Fix the warning reported by 'make C=1 W=1': WARNING: modpost: missing MODULE_DESCRIPTION() in kernel/kcsan/kcsan_test.o Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Reviewed-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2024-06-06Merge tag 'net-6.10-rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Jakub Kicinski: "Including fixes from BPF and big collection of fixes for WiFi core and drivers. Current release - regressions: - vxlan: fix regression when dropping packets due to invalid src addresses - bpf: fix a potential use-after-free in bpf_link_free() - xdp: revert support for redirect to any xsk socket bound to the same UMEM as it can result in a corruption - virtio_net: - add missing lock protection when reading return code from control_buf - fix false-positive lockdep splat in DIM - Revert "wifi: wilc1000: convert list management to RCU" - wifi: ath11k: fix error path in ath11k_pcic_ext_irq_config Previous releases - regressions: - rtnetlink: make the "split" NLM_DONE handling generic, restore the old behavior for two cases where we started coalescing those messages with normal messages, breaking sloppily-coded userspace - wifi: - cfg80211: validate HE operation element parsing - cfg80211: fix 6 GHz scan request building - mt76: mt7615: add missing chanctx ops - ath11k: move power type check to ASSOC stage, fix connecting to 6 GHz AP - ath11k: fix WCN6750 firmware crash caused by 17 num_vdevs - rtlwifi: ignore IEEE80211_CONF_CHANGE_RETRY_LIMITS - iwlwifi: mvm: fix a crash on 7265 Previous releases - always broken: - ncsi: prevent multi-threaded channel probing, a spec violation - vmxnet3: disable rx data ring on dma allocation failure - ethtool: init tsinfo stats if requested, prevent unintentionally reporting all-zero stats on devices which don't implement any - dst_cache: fix possible races in less common IPv6 features - tcp: auth: don't consider TCP_CLOSE to be in TCP_AO_ESTABLISHED - ax25: fix two refcounting bugs - eth: ionic: fix kernel panic in XDP_TX action Misc: - tcp: count CLOSE-WAIT sockets for TCP_MIB_CURRESTAB" * tag 'net-6.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (107 commits) selftests: net: lib: set 'i' as local selftests: net: lib: avoid error removing empty netns name selftests: net: lib: support errexit with busywait net: ethtool: fix the error condition in ethtool_get_phy_stats_ethtool() ipv6: fix possible race in __fib6_drop_pcpu_from() af_unix: Annotate data-race of sk->sk_shutdown in sk_diag_fill(). af_unix: Use skb_queue_len_lockless() in sk_diag_show_rqlen(). af_unix: Use skb_queue_empty_lockless() in unix_release_sock(). af_unix: Use unix_recvq_full_lockless() in unix_stream_connect(). af_unix: Annotate data-race of net->unx.sysctl_max_dgram_qlen. af_unix: Annotate data-races around sk->sk_sndbuf. af_unix: Annotate data-races around sk->sk_state in UNIX_DIAG. af_unix: Annotate data-race of sk->sk_state in unix_stream_read_skb(). af_unix: Annotate data-races around sk->sk_state in sendmsg() and recvmsg(). af_unix: Annotate data-race of sk->sk_state in unix_accept(). af_unix: Annotate data-race of sk->sk_state in unix_stream_connect(). af_unix: Annotate data-races around sk->sk_state in unix_write_space() and poll(). af_unix: Annotate data-race of sk->sk_state in unix_inq_len(). af_unix: Annodate data-races around sk->sk_state for writers. af_unix: Set sk->sk_state under unix_state_lock() for truly disconencted peer. ...
2024-06-06ftrace: Rename dup_hash() and comment itSteven Rostedt (Google)
The name "dup_hash()" is a misnomer as it does not duplicate the hash that is passed in, but instead moves its entities from that hash to a newly allocated one. Rename it to "__move_hash()" (using starting underscores as it is an internal function), and add some comments about what it does. Link: https://lore.kernel.org/linux-trace-kernel/20240605180408.537723591@goodmis.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-06tracing: Fix trace_pid_list_free() kernel-docJeff Johnson
make C=1 reports: kernel/trace/pid_list.c:458: warning: Function parameter or struct member 'pid_list' not described in 'trace_pid_list_free' Add the missing parameter to the trace_pid_list_free() kernel-doc. Link: https://lore.kernel.org/linux-trace-kernel/20240506-trace_pid_list_free-kdoc-v1-1-c70f0ae29144@quicinc.com Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-05ftrace: Add back ftrace_update_trampoline() to ftrace_update_pid_func()Steven Rostedt (Google)
The update to the ops trampoline done by the function ftrace_update_trampoline() was accidentally removed from ftrace_update_pid_func(). Add it back. Link: https://lore.kernel.org/linux-trace-kernel/20240605205337.6115e9a5@gandalf.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: df3ec5da6a1e ("function_graph: Add pid tracing back to function graph tracer") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-05irqdomain: Add missing parameter descriptions in kernel-doc commentsHerve Codina
During compilation, several warning of the following form were raised: Function parameter or struct member 'x' not described in 'yyy' Add the missing function parameter descriptions. Signed-off-by: Herve Codina <herve.codina@bootlin.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20240527161450.326615-10-herve.codina@bootlin.com
2024-06-05sched/balance: Skip unnecessary updates to idle load balancer's flagsTim Chen
We observed that the overhead on trigger_load_balance(), now renamed sched_balance_trigger(), has risen with a system's core counts. For an OLTP workload running 6.8 kernel on a 2 socket x86 systems having 96 cores/socket, we saw that 0.7% cpu cycles are spent in trigger_load_balance(). On older systems with fewer cores/socket, this function's overhead was less than 0.1%. The cause of this overhead was that there are multiple cpus calling kick_ilb(flags), updating the balancing work needed to a common idle load balancer cpu. The ilb_cpu's flags field got updated unconditionally with atomic_fetch_or(). The atomic read and writes to ilb_cpu's flags causes much cache bouncing and cpu cycles overhead. This is seen in the annotated profile below. kick_ilb(): if (ilb_cpu < 0) test %r14d,%r14d ↑ js 6c flags = atomic_fetch_or(flags, nohz_flags(ilb_cpu)); mov $0x2d600,%rdi movslq %r14d,%r8 mov %rdi,%rdx add -0x7dd0c3e0(,%r8,8),%rdx arch_atomic_read(): 0.01 mov 0x64(%rdx),%esi 35.58 add $0x64,%rdx arch_atomic_fetch_or(): static __always_inline int arch_atomic_fetch_or(int i, atomic_t *v) { int val = arch_atomic_read(v); do { } while (!arch_atomic_try_cmpxchg(v, &val, val | i)); 0.03 157: mov %r12d,%ecx arch_atomic_try_cmpxchg(): return arch_try_cmpxchg(&v->counter, old, new); 0.00 mov %esi,%eax arch_atomic_fetch_or(): do { } while (!arch_atomic_try_cmpxchg(v, &val, val | i)); or %esi,%ecx arch_atomic_try_cmpxchg(): return arch_try_cmpxchg(&v->counter, old, new); 0.01 lock cmpxchg %ecx,(%rdx) 42.96 ↓ jne 2d2 kick_ilb(): With instrumentation, we found that 81% of the updates do not result in any change in the ilb_cpu's flags. That is, multiple cpus are asking the ilb_cpu to do the same things over and over again, before the ilb_cpu has a chance to run NOHZ load balance. Skip updates to ilb_cpu's flags if no new work needs to be done. Such updates do not change ilb_cpu's NOHZ flags. This requires an extra atomic read but it is less expensive than frequent unnecessary atomic updates that generate cache bounces. We saw that on the OLTP workload, cpu cycles from trigger_load_balance() (or sched_balance_trigger()) got reduced from 0.7% to 0.2%. Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20240531205452.65781-1-tim.c.chen@linux.intel.com
2024-06-05idle: Remove stale RCU commentChristian Loehle
The call of rcu_idle_enter() from within cpuidle_idle_call() was removed in commit 1098582a0f6c ("sched,idle,rcu: Push rcu_idle deeper into the idle path") which makes the comment out of place. Signed-off-by: Christian Loehle <christian.loehle@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/5b936388-47df-4050-9229-6617a6c2bba5@arm.com
2024-06-05perf/core: Fix missing wakeup when waiting for context referenceHaifeng Xu
In our production environment, we found many hung tasks which are blocked for more than 18 hours. Their call traces are like this: [346278.191038] __schedule+0x2d8/0x890 [346278.191046] schedule+0x4e/0xb0 [346278.191049] perf_event_free_task+0x220/0x270 [346278.191056] ? init_wait_var_entry+0x50/0x50 [346278.191060] copy_process+0x663/0x18d0 [346278.191068] kernel_clone+0x9d/0x3d0 [346278.191072] __do_sys_clone+0x5d/0x80 [346278.191076] __x64_sys_clone+0x25/0x30 [346278.191079] do_syscall_64+0x5c/0xc0 [346278.191083] ? syscall_exit_to_user_mode+0x27/0x50 [346278.191086] ? do_syscall_64+0x69/0xc0 [346278.191088] ? irqentry_exit_to_user_mode+0x9/0x20 [346278.191092] ? irqentry_exit+0x19/0x30 [346278.191095] ? exc_page_fault+0x89/0x160 [346278.191097] ? asm_exc_page_fault+0x8/0x30 [346278.191102] entry_SYSCALL_64_after_hwframe+0x44/0xae The task was waiting for the refcount become to 1, but from the vmcore, we found the refcount has already been 1. It seems that the task didn't get woken up by perf_event_release_kernel() and got stuck forever. The below scenario may cause the problem. Thread A Thread B ... ... perf_event_free_task perf_event_release_kernel ... acquire event->child_mutex ... get_ctx ... release event->child_mutex acquire ctx->mutex ... perf_free_event (acquire/release event->child_mutex) ... release ctx->mutex wait_var_event acquire ctx->mutex acquire event->child_mutex # move existing events to free_list release event->child_mutex release ctx->mutex put_ctx ... ... In this case, all events of the ctx have been freed, so we couldn't find the ctx in free_list and Thread A will miss the wakeup. It's thus necessary to add a wakeup after dropping the reference. Fixes: 1cf8dfe8a661 ("perf/core: Fix race between close() and fork()") Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20240513103948.33570-1-haifeng.xu@shopee.com
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