| Message ID | 20221103170015.4124426-1-ardb@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: fix rodata=full again | expand |
On Thu, Nov 03, 2022 at 06:00:15PM +0100, Ard Biesheuvel wrote: > Commit 2e8cff0a0eee87b2 ("arm64: fix rodata=full") addressed a couple of > issues with the rodata= kernel command line option, which is not a > simple boolean on arm64, and inadvertently got broken due to changes in > the generic bool handling. > > Unfortunately, the resulting code never clears the rodata_full boolean > variable if it defaults to true and rodata=on or rodata=off is passed, > as the generic code is not aware of the existence of this variable. > > Given the way this code is plumbed together, clearing rodata_full when > returning false from arch_parse_debug_rodata() may result in > inconsistencies if the generic code decides that it cannot parse the > right hand side, so the best way to deal with this is to only take > rodata_full in account if rodata_enabled is also true. > > Fixes: 2e8cff0a0eee87b2 ("arm64: fix rodata=full") > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > --- > arch/arm64/mm/pageattr.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c > index d107c3d434e22455..5922178d7a064c1c 100644 > --- a/arch/arm64/mm/pageattr.c > +++ b/arch/arm64/mm/pageattr.c > @@ -26,7 +26,7 @@ bool can_set_direct_map(void) > * mapped at page granularity, so that it is possible to > * protect/unprotect single pages. > */ > - return rodata_full || debug_pagealloc_enabled() || > + return (rodata_enabled && rodata_full) || debug_pagealloc_enabled() || > IS_ENABLED(CONFIG_KFENCE); > } > > @@ -102,7 +102,8 @@ static int change_memory_common(unsigned long addr, int numpages, > * If we are manipulating read-only permissions, apply the same > * change to the linear mapping of the pages that back this VM area. > */ > - if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY || > + if (rodata_enabled && > + rodata_full && (pgprot_val(set_mask) == PTE_RDONLY || > pgprot_val(clear_mask) == PTE_RDONLY)) { > for (i = 0; i < area->nr_pages; i++) { > __change_memory_common((u64)page_address(area->pages[i]), > -- > 2.35.1 Hmm, I dislike how error-prone this is, but thanks for the fix: Acked-by: Will Deacon <will@kernel.org> Will
On Thu, 3 Nov 2022 18:00:15 +0100, Ard Biesheuvel wrote: > Commit 2e8cff0a0eee87b2 ("arm64: fix rodata=full") addressed a couple of > issues with the rodata= kernel command line option, which is not a > simple boolean on arm64, and inadvertently got broken due to changes in > the generic bool handling. > > Unfortunately, the resulting code never clears the rodata_full boolean > variable if it defaults to true and rodata=on or rodata=off is passed, > as the generic code is not aware of the existence of this variable. > > [...] Applied to arm64 (for-next/fixes), thanks! [1/1] arm64: fix rodata=full again https://git.kernel.org/arm64/c/2081b3bd0c11
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index d107c3d434e22455..5922178d7a064c1c 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -26,7 +26,7 @@ bool can_set_direct_map(void) * mapped at page granularity, so that it is possible to * protect/unprotect single pages. */ - return rodata_full || debug_pagealloc_enabled() || + return (rodata_enabled && rodata_full) || debug_pagealloc_enabled() || IS_ENABLED(CONFIG_KFENCE); } @@ -102,7 +102,8 @@ static int change_memory_common(unsigned long addr, int numpages, * If we are manipulating read-only permissions, apply the same * change to the linear mapping of the pages that back this VM area. */ - if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY || + if (rodata_enabled && + rodata_full && (pgprot_val(set_mask) == PTE_RDONLY || pgprot_val(clear_mask) == PTE_RDONLY)) { for (i = 0; i < area->nr_pages; i++) { __change_memory_common((u64)page_address(area->pages[i]),
Commit 2e8cff0a0eee87b2 ("arm64: fix rodata=full") addressed a couple of issues with the rodata= kernel command line option, which is not a simple boolean on arm64, and inadvertently got broken due to changes in the generic bool handling. Unfortunately, the resulting code never clears the rodata_full boolean variable if it defaults to true and rodata=on or rodata=off is passed, as the generic code is not aware of the existence of this variable. Given the way this code is plumbed together, clearing rodata_full when returning false from arch_parse_debug_rodata() may result in inconsistencies if the generic code decides that it cannot parse the right hand side, so the best way to deal with this is to only take rodata_full in account if rodata_enabled is also true. Fixes: 2e8cff0a0eee87b2 ("arm64: fix rodata=full") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- arch/arm64/mm/pageattr.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)