memory_failure(9)

💖 memory_failure(9) 💖

ok so you're reading the Kernel API Manual bestie, and this is the page for memory_failure(9) — literally the function that handles a memory failure of a page. yes THAT kind of failure. the hardware kind. buckle up 🎀

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✨ NAME ✨

memory_failure — Handle memory failure of a page. that's it, that's the whole vibe. when a page goes bad, this is the girl they call 💅

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✨ SYNOPSIS ✨

int memory_failure (unsigned long pfn , int flags );

like, it takes two things and returns an int. concise. iconic. no notes 👑

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✨ ARGUMENTS ✨

• pfn — Page Number of the corrupted page. that's the address of the page that's gone bad 😭 the one having a whole crisis.
• flags — fine tune action taken. itty bitty knobs to nudge how it behaves, iykyk 🎛️

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✨ DESCRIPTION ✨

okay so picture this 🫶 — the low level machine check code of an architecture notices that hardware memory corruption happened on a page. and then it calls this function. and memory_failure tries its best to recover, which — ngl — includes dropping pages, killing processes etc. like, it's doing the absolute most to save the day, and sometimes the day gets saved by literally ending a process 💀 no cap.

this function is primarily of use for corruptions that happen outside the current execution context — for example when a background scrubber detects it 🧹✨ (scrubber said "not on my watch").

🚨 IMPORTANT VIBE CHECK: this must run in process context (e.g. a work queue) with interrupts enabled and no spinlocks held. do not try this from a spinlock bestie, it will not slay, it will not go well 🙈

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✨ RETURN ✨

so the return values are giving a whole spectrum, let's go through them one by one:

• 0 — success 🎉 periodt.
• -ENXIO — memory not managed by the kernel. not our page, not our problem 🫥
• -EOPNOTSUPP — hwpoison_filter filtered the error event. the bouncer said no ✋
• -EHWPOISON — the page was already poisoned, potentially kill process. she's already been through it 😭 maybe someone's getting killed over it, lowkey.
• other negative values — failure. yeah. just... failure. 💀

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✨ SEE ALSO ✨

go read these next, fr fr, they're the rest of the friend group 👯‍♀️:

• Kernel file ./mm/memory-failure.c
• MF_ATTR_RO(9)
• get_hwpoison_page(9)
• mf_dax_kill_procs(9)
• memory_failure_pfn(9)
• memory_failure_queue(9)
• unpoison_memory(9)
• soft_offline_page(9)

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okay that's the whole page!! this came from ./mm and it's dated October 2026 🌸 so yeah, that's the source, that's the version, that's the date — mwah, go forth and handle those failures bestie 🦋✨💖