+ uprobes-use-pagesize-aligned-virtual-address-when-replacing-pages.patch added to mm-hotfixes-unstable branch

+ uprobes-use-pagesize-aligned-virtual-address-when-replacing-pages.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: uprobes: use pagesize-aligned virtual address when replacing pages
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     uprobes-use-pagesize-aligned-virtual-address-when-replacing-pages.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/uprobes-use-pagesize-aligned-virtual-address-when-replacing-pages.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: David Hildenbrand <david@redhat.com>
Subject: uprobes: use pagesize-aligned virtual address when replacing pages
Date: Mon, 15 Jan 2024 11:07:31 +0100

uprobes passes an unaligned page mapping address to
folio_add_new_anon_rmap(), which ends up triggering a VM_BUG_ON() we
recently extended in commit 372cbd4d5a066 ("mm: non-pmd-mappable, large
folios for folio_add_new_anon_rmap()").

Arguably, this is uprobes code doing something wrong; however, for the
time being it would have likely worked in rmap code because
__folio_set_anon() would set folio->index to the same value.

Looking at __replace_page(), we'd also pass slightly wrong values to
mmu_notifier_range_init(), page_vma_mapped_walk(), flush_cache_page(),
ptep_clear_flush() and set_pte_at_notify().  I suspect most of them are
fine, but let's just mark the introducing commit as the one needed fixing.
I don't think CC stable is warranted.

We'll add more sanity checks in rmap code separately, to make sure that we
always get properly aligned addresses.

Link: https://lkml.kernel.org/r/20240115100731.91007-1-david@redhat.com
Fixes: c517ee744b96 ("uprobes: __replace_page() should not use page_address_in_vma()")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Jiri Olsa <jolsa@kernel.org>
Closes: https://lkml.kernel.org/r/ZaMR2EWN-HvlCfUl@krava
Tested-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/events/uprobes.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/events/uprobes.c~uprobes-use-pagesize-aligned-virtual-address-when-replacing-pages
+++ a/kernel/events/uprobes.c
@@ -537,7 +537,7 @@ retry:
 		}
 	}
 
-	ret = __replace_page(vma, vaddr, old_page, new_page);
+	ret = __replace_page(vma, vaddr & PAGE_MASK, old_page, new_page);
 	if (new_page)
 		put_page(new_page);
 put_old:
_

Patches currently in -mm which might be from david@redhat.com are

uprobes-use-pagesize-aligned-virtual-address-when-replacing-pages.patch