From 0c66c6f4e21cb22220cbd8821c5c73fc157d20dc Mon Sep 17 00:00:00 2001 From: Yongqiang Liu Date: Thu, 7 Mar 2024 13:05:09 +0100 Subject: ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since commit a4d5613c4dc6 ("arm: extend pfn_valid to take into account freed memory map alignment") changes the semantics of pfn_valid() to check presence of the memory map for a PFN. A valid page for an address which is reserved but not mapped by the kernel[1], the system crashed during some uio test with the following memory layout: node 0: [mem 0x00000000c0a00000-0x00000000cc8fffff] node 0: [mem 0x00000000d0000000-0x00000000da1fffff] the uio layout is：0xc0900000, 0x100000 the crash backtrace like: Unable to handle kernel paging request at virtual address bff00000 [...] CPU: 1 PID: 465 Comm: startapp.bin Tainted: G O 5.10.0 #1 Hardware name: Generic DT based system PC is at b15_flush_kern_dcache_area+0x24/0x3c LR is at __sync_icache_dcache+0x6c/0x98 [...] (b15_flush_kern_dcache_area) from (__sync_icache_dcache+0x6c/0x98) (__sync_icache_dcache) from (set_pte_at+0x28/0x54) (set_pte_at) from (remap_pfn_range+0x1a0/0x274) (remap_pfn_range) from (uio_mmap+0x184/0x1b8 [uio]) (uio_mmap [uio]) from (__mmap_region+0x264/0x5f4) (__mmap_region) from (__do_mmap_mm+0x3ec/0x440) (__do_mmap_mm) from (do_mmap+0x50/0x58) (do_mmap) from (vm_mmap_pgoff+0xfc/0x188) (vm_mmap_pgoff) from (ksys_mmap_pgoff+0xac/0xc4) (ksys_mmap_pgoff) from (ret_fast_syscall+0x0/0x5c) Code: e0801001 e2423001 e1c00003 f57ff04f (ee070f3e) ---[ end trace 09cf0734c3805d52 ]--- Kernel panic - not syncing: Fatal exception So check if PG_reserved was set to solve this issue. [1]: https://lore.kernel.org/lkml/Zbtdue57RO0QScJM@linux.ibm.com/ Fixes: a4d5613c4dc6 ("arm: extend pfn_valid to take into account freed memory map alignment") Suggested-by: Mike Rapoport Signed-off-by: Yongqiang Liu Signed-off-by: Russell King (Oracle) --- arch/arm/mm/flush.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index d19d140a10c7..0749cf8a6637 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -296,6 +296,9 @@ void __sync_icache_dcache(pte_t pteval) return; folio = page_folio(pfn_to_page(pfn)); + if (folio_test_reserved(folio)) + return; + if (cache_is_vipt_aliasing()) mapping = folio_flush_mapping(folio); else -- cgit