| Message ID | 20250124-riscv_optimize_entry-v3-4-869f36b9e43b@rivosinc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | entry: Move ret_from_fork() to C and inline syscall_exit_to_user_mode() | expand |
Hello,
kernel test robot noticed "WARNING:at_include/linux/entry-common.h:#ret_from_fork" on:
commit: af2a35e015974bdfa788eebda365a2896b2db87c ("[PATCH v3 4/4] entry: Inline syscall_exit_to_user_mode()")
url: https://github.com/intel-lab-lkp/linux/commits/Charlie-Jenkins/riscv-entry-Convert-ret_from_fork-to-C/20250125-063418
patch link: https://lore.kernel.org/all/20250124-riscv_optimize_entry-v3-4-869f36b9e43b@rivosinc.com/
patch subject: [PATCH v3 4/4] entry: Inline syscall_exit_to_user_mode()
in testcase: boot
config: x86_64-randconfig-004-20250126
compiler: gcc-12
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
(please refer to attached dmesg/kmsg for entire log/backtrace)
+---------------------------------------------------------------+------------+------------+
| | d05f6a7fc5 | af2a35e015 |
+---------------------------------------------------------------+------------+------------+
| boot_successes | 21 | 0 |
| boot_failures | 0 | 21 |
| WARNING:at_include/linux/entry-common.h:#ret_from_fork | 0 | 21 |
| RIP:ret_from_fork | 0 | 21 |
| WARNING:at_include/linux/entry-common.h:#do_int80_emulation | 0 | 15 |
| RIP:do_int80_emulation | 0 | 15 |
| WARNING:at_include/linux/entry-common.h:#__do_fast_syscall_32 | 0 | 15 |
| RIP:__do_fast_syscall_32 | 0 | 15 |
| WARNING:at_include/linux/entry-common.h:#do_syscall_64 | 0 | 6 |
| RIP:do_syscall_64 | 0 | 6 |
+---------------------------------------------------------------+------------+------------+
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202501272352.d9bc5c3-lkp@intel.com
[ 112.344122][ T69] ------------[ cut here ]------------
[ 112.345019][ T69] WARNING: CPU: 0 PID: 69 at include/linux/entry-common.h:397 ret_from_fork (include/linux/entry-common.h:397 include/linux/entry-common.h:449 arch/x86/kernel/process.c:156)
[ 112.346485][ T69] Modules linked in:
[ 112.347163][ T69] CPU: 0 UID: 0 PID: 69 Comm: modprobe Not tainted 6.13.0-00004-gaf2a35e01597 #1 214e9f59286a53f9934969c01f519fb8074cbd24
[ 112.348970][ T69] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 112.350385][ T69] RIP: 0010:ret_from_fork (include/linux/entry-common.h:397 include/linux/entry-common.h:449 arch/x86/kernel/process.c:156)
[ 112.351202][ T69] Code: f8 83 e0 07 83 c0 03 38 d0 7c 09 84 d2 74 05 e8 e2 f1 4a 00 41 8b 85 a8 56 1f 00 65 ff 0d 25 06 1b 7f 75 05 0f 1f 44 00 00 90 <0f> 0b 90 9c 58 0f ba e0 09 72 1b 90 48 c7 c7 00 ad 22 83 48 63 f5
All code
========
0: f8 clc
1: 83 e0 07 and $0x7,%eax
4: 83 c0 03 add $0x3,%eax
7: 38 d0 cmp %dl,%al
9: 7c 09 jl 0x14
b: 84 d2 test %dl,%dl
d: 74 05 je 0x14
f: e8 e2 f1 4a 00 call 0x4af1f6
14: 41 8b 85 a8 56 1f 00 mov 0x1f56a8(%r13),%eax
1b: 65 ff 0d 25 06 1b 7f decl %gs:0x7f1b0625(%rip) # 0x7f1b0647
22: 75 05 jne 0x29
24: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
29: 90 nop
2a:* 0f 0b ud2 <-- trapping instruction
2c: 90 nop
2d: 9c pushf
2e: 58 pop %rax
2f: 0f ba e0 09 bt $0x9,%eax
33: 72 1b jb 0x50
35: 90 nop
36: 48 c7 c7 00 ad 22 83 mov $0xffffffff8322ad00,%rdi
3d: 48 63 f5 movslq %ebp,%rsi
Code starting with the faulting instruction
===========================================
0: 0f 0b ud2
2: 90 nop
3: 9c pushf
4: 58 pop %rax
5: 0f ba e0 09 bt $0x9,%eax
9: 72 1b jb 0x26
b: 90 nop
c: 48 c7 c7 00 ad 22 83 mov $0xffffffff8322ad00,%rdi
13: 48 63 f5 movslq %ebp,%rsi
[ 112.353759][ T69] RSP: 0000:ffffc900016eff20 EFLAGS: 00010246
[ 112.354637][ T69] RAX: 000000000001256c RBX: ffffc900016eff48 RCX: 1ffffffff0aab891
[ 112.355762][ T69] RDX: 1ffff11075d7ea00 RSI: 0000000000000006 RDI: ffff8883aebf56a8
[ 112.356876][ T69] RBP: 000000000000003b R08: fffffbfff0aac275 R09: 0000000000000000
[ 112.358011][ T69] R10: ffffffff8133b7bb R11: fffffbfff0aac274 R12: 0000000000000000
[ 112.359131][ T69] R13: ffff8883aea00000 R14: 0000000000000000 R15: 0000000000000000
[ 112.360256][ T69] FS: 0000000000000000(0000) GS:ffff8883aea00000(0000) knlGS:0000000000000000
[ 112.361495][ T69] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 112.362410][ T69] CR2: 00007fff006efef9 CR3: 000000014ab4d000 CR4: 00000000000406b0
[ 112.364674][ T69] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 112.365489][ T69] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 112.366294][ T69] Call Trace:
[ 112.366677][ T69] <TASK>
[ 112.367020][ T69] ? __warn (kernel/panic.c:748)
[ 112.367509][ T69] ? ret_from_fork (include/linux/entry-common.h:397 include/linux/entry-common.h:449 arch/x86/kernel/process.c:156)
[ 112.368006][ T69] ? report_bug (lib/bug.c:201 lib/bug.c:219)
[ 112.368605][ T69] ? ret_from_fork (include/linux/entry-common.h:397 include/linux/entry-common.h:449 arch/x86/kernel/process.c:156)
[ 112.369094][ T69] ? handle_bug (arch/x86/kernel/traps.c:285)
[ 112.369551][ T69] ? exc_invalid_op (arch/x86/kernel/traps.c:309 (discriminator 1))
[ 112.370039][ T69] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:621)
[ 112.370572][ T69] ? trace_irq_enable+0xa1/0xda
[ 112.371195][ T69] ? ret_from_fork (include/linux/entry-common.h:397 include/linux/entry-common.h:449 arch/x86/kernel/process.c:156)
[ 112.371685][ T69] ? umh_complete (kernel/umh.c:64)
[ 112.372160][ T69] ret_from_fork_asm (arch/x86/entry/entry_64.S:254)
[ 112.372670][ T69] </TASK>
[ 112.373019][ T69] irq event stamp: 1233
[ 112.373460][ T69] hardirqs last enabled at (1243): __up_console_sem (arch/x86/include/asm/irqflags.h:26 (discriminator 1) arch/x86/include/asm/irqflags.h:87 (discriminator 1) arch/x86/include/asm/irqflags.h:147 (discriminator 1) kernel/printk/printk.c:344 (discriminator 1))
[ 112.374413][ T69] hardirqs last disabled at (1254): __up_console_sem (kernel/printk/printk.c:342 (discriminator 1))
[ 112.375342][ T69] softirqs last enabled at (928): handle_softirqs (arch/x86/include/asm/preempt.h:26 kernel/softirq.c:408 kernel/softirq.c:589)
[ 112.376269][ T69] softirqs last disabled at (917): __irq_exit_rcu (kernel/softirq.c:435 kernel/softirq.c:662)
[ 112.377174][ T69] ---[ end trace 0000000000000000 ]---
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250127/202501272352.d9bc5c3-lkp@intel.com
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index fc61d0205c97084acc89c8e45e088946f5e6d9b2..ee1c400bc0eb0ebb5850f95e856b819fca7b3577 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -14,6 +14,7 @@ #include <linux/kmsan.h> #include <asm/entry-common.h> +#include <asm/syscall.h> /* * Define dummy _TIF work flags if not defined by the architecture or for @@ -366,6 +367,15 @@ static __always_inline void exit_to_user_mode(void) lockdep_hardirqs_on(CALLER_ADDR0); } +/** + * syscall_exit_work - Handle work before returning to user mode + * @regs: Pointer to current pt_regs + * @work: Current thread syscall work + * + * Do one-time syscall specific work. + */ +void syscall_exit_work(struct pt_regs *regs, unsigned long work); + /** * syscall_exit_to_user_mode_work - Handle work before returning to user mode * @regs: Pointer to currents pt_regs @@ -379,7 +389,30 @@ static __always_inline void exit_to_user_mode(void) * make the final state transitions. Interrupts must stay disabled between * return from this function and the invocation of exit_to_user_mode(). */ -void syscall_exit_to_user_mode_work(struct pt_regs *regs); +static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs) +{ + unsigned long work = READ_ONCE(current_thread_info()->syscall_work); + unsigned long nr = syscall_get_nr(current, regs); + + CT_WARN_ON(ct_state() != PERF_CONTEXT_KERNEL); + + if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { + if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr)) + local_irq_enable(); + } + + rseq_syscall(regs); + + /* + * Do one-time syscall specific work. If these work items are + * enabled, we want to run them exactly once per syscall exit with + * interrupts enabled. + */ + if (unlikely(work & SYSCALL_WORK_EXIT)) + syscall_exit_work(regs, work); + local_irq_disable_exit_to_user(); + exit_to_user_mode_prepare(regs); +} /** * syscall_exit_to_user_mode - Handle work before returning to user mode @@ -410,7 +443,13 @@ void syscall_exit_to_user_mode_work(struct pt_regs *regs); * exit_to_user_mode(). This function is preferred unless there is a * compelling architectural reason to use the separate functions. */ -void syscall_exit_to_user_mode(struct pt_regs *regs); +static __always_inline void syscall_exit_to_user_mode(struct pt_regs *regs) +{ + instrumentation_begin(); + syscall_exit_to_user_mode_work(regs); + instrumentation_end(); + exit_to_user_mode(); +} /** * irqentry_enter_from_user_mode - Establish state before invoking the irq handler diff --git a/kernel/entry/common.c b/kernel/entry/common.c index e33691d5adf7aab4af54cf2bf8e5ef5bd6ad1424..f55e421fb196dd5f9d4e34dd85ae096c774cf879 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -146,7 +146,7 @@ static inline bool report_single_step(unsigned long work) return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP; } -static void syscall_exit_work(struct pt_regs *regs, unsigned long work) +void syscall_exit_work(struct pt_regs *regs, unsigned long work) { bool step; @@ -173,53 +173,6 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long work) ptrace_report_syscall_exit(regs, step); } -/* - * Syscall specific exit to user mode preparation. Runs with interrupts - * enabled. - */ -static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs) -{ - unsigned long work = READ_ONCE(current_thread_info()->syscall_work); - unsigned long nr = syscall_get_nr(current, regs); - - CT_WARN_ON(ct_state() != CT_STATE_KERNEL); - - if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { - if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr)) - local_irq_enable(); - } - - rseq_syscall(regs); - - /* - * Do one-time syscall specific work. If these work items are - * enabled, we want to run them exactly once per syscall exit with - * interrupts enabled. - */ - if (unlikely(work & SYSCALL_WORK_EXIT)) - syscall_exit_work(regs, work); -} - -static __always_inline void __syscall_exit_to_user_mode_work(struct pt_regs *regs) -{ - syscall_exit_to_user_mode_prepare(regs); - local_irq_disable_exit_to_user(); - exit_to_user_mode_prepare(regs); -} - -void syscall_exit_to_user_mode_work(struct pt_regs *regs) -{ - __syscall_exit_to_user_mode_work(regs); -} - -__visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs) -{ - instrumentation_begin(); - __syscall_exit_to_user_mode_work(regs); - instrumentation_end(); - exit_to_user_mode(); -} - noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs) { enter_from_user_mode(regs);
Architectures using the generic entry code can be optimized by having syscall_exit_to_user_mode inlined. Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> --- include/linux/entry-common.h | 43 ++++++++++++++++++++++++++++++++++++-- kernel/entry/common.c | 49 +------------------------------------------- 2 files changed, 42 insertions(+), 50 deletions(-)