__kcsan_mb(9)

💅 __kcsan_mb(9) — bestie, it's giving full memory barrier instrumentation

okay so real talk, we're deep in the Kernel API Manual (section 9, the kernel-adjacent girlies know) and today's main character is __kcsan_mb. that name? lowkey cryptic. the job? a full memory barrier, but make it instrumented. no cap.

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✨ NAME ✨

__kcsan_mb — full memory barrier instrumentation 🧠⚡

like, it's the KCSAN-flavored full memory barrier. that's the whole vibe.

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🎀 SYNOPSIS 🎀

void __kcsan_mb (void );

yep. that's it. she takes nothing, she returns nothing, she simply is. iconic behavior honestly.

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🦋 ARGUMENTS 🦋

• void — no arguments 💀 fr fr, zero. nada. the function said "i don't need input, i'm built different."

ngl there is literally nothing else in this section and i respect the confidence.

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🌈 SEE ALSO 🌈

okay so this is the part where the manpage just dumps the whole friend group on you 😭 and every single one of them is a real one. no skipping, we're listing all of them because they all ate:

• the kernel source file ./include/linux/kcsan-checks.h — that's the home base 🏠
• __kcsan_check_access(9)
• __kcsan_wmb(9)
• __kcsan_rmb(9)
• __kcsan_release(9)
• kcsan_disable_current(9)
• kcsan_enable_current(9)
• kcsan_nestable_atomic_begin(9)
• kcsan_nestable_atomic_end(9)
• kcsan_flat_atomic_begin(9)
• kcsan_flat_atomic_end(9)
• kcsan_atomic_next(9)
• kcsan_set_access_mask(9)
• kcsan_begin_scoped_access(9)
• kcsan_end_scoped_access(9)
• __kcsan_check_read(9)
• __kcsan_check_write(9)
• __kcsan_check_read_write(9)
• kcsan_check_read(9)
• kcsan_check_write(9)
• kcsan_check_read_write(9)
• ASSERT_EXCLUSIVE_WRITER(9)
• ASSERT_EXCLUSIVE_WRITER_SCOPED(9)
• ASSERT_EXCLUSIVE_ACCESS(9)
• ASSERT_EXCLUSIVE_ACCESS_SCOPED(9)
• ASSERT_EXCLUSIVE_BITS(9)

that's the whole group chat bestie, go say hi 🫶

lowkey reminder: this page only tells you what __kcsan_mb is. the actual details of how KCSAN instruments any of this live in those other pages — don't come for me, i'm just the messenger 💅

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so yeah. __kcsan_mb(9), full memory barrier instrumentation, takes void, gives void, hangs out in ./include/linux/kcsan-checks.h with all her friends. slay. periodt. 🔥👑

this little love letter comes to you from the Kernel API Manual, dated October 2026, sourced from ./include/linux — mwah, take care of her 💖✨