On Thu, Feb 05, 2026 at 11:57:25AM +0100, Carlos López wrote: > kmap_atomic() has been deprecated for a few years, and kmap_local_page() > should be used instead, so replace it. Since the uprobes code relied on > kmap_atomic() disabling page faults to access user pages, add the > required calls to keep the existing behavior.
Are those pagefault_disable()s really needed here, or is this just cargo-culting? > Signed-off-by: Carlos López <[email protected]> > --- > kernel/events/uprobes.c | 22 ++++++++++++++++------ > 1 file changed, 16 insertions(+), 6 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index d546d32390a8..38898435acfe 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -179,16 +179,24 @@ bool __weak is_trap_insn(uprobe_opcode_t *insn) > > void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void > *dst, int len) > { > - void *kaddr = kmap_atomic(page); > + void *kaddr = kmap_local_page(page); > + > + pagefault_disable(); > memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len); > - kunmap_atomic(kaddr); > + pagefault_enable(); > + > + kunmap_local(kaddr); > } > > static void copy_to_page(struct page *page, unsigned long vaddr, const void > *src, int len) > { > - void *kaddr = kmap_atomic(page); > + void *kaddr = kmap_local_page(page); > + > + pagefault_disable(); > memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len); > - kunmap_atomic(kaddr); > + pagefault_enable(); > + > + kunmap_local(kaddr); > } > > static int verify_opcode(struct page *page, unsigned long vaddr, > uprobe_opcode_t *insn, > @@ -323,9 +331,10 @@ __update_ref_ctr(struct mm_struct *mm, unsigned long > vaddr, short d) > return ret == 0 ? -EBUSY : ret; > } > > - kaddr = kmap_atomic(page); > + kaddr = kmap_local_page(page); > ptr = kaddr + (vaddr & ~PAGE_MASK); > > + pagefault_disable(); > if (unlikely(*ptr + d < 0)) { > pr_warn("ref_ctr going negative. vaddr: 0x%lx, " > "curr val: %d, delta: %d\n", vaddr, *ptr, d); > @@ -336,7 +345,8 @@ __update_ref_ctr(struct mm_struct *mm, unsigned long > vaddr, short d) > *ptr += d; > ret = 0; > out: > - kunmap_atomic(kaddr); > + pagefault_enable(); > + kunmap_local(kaddr); > put_page(page); > return ret; > } > > base-commit: f14faaf3a1fb3b9e4cf2e56269711fb85fba9458 > -- > 2.51.0 >
