Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 31 Jan 2024 08:16:06 -0800 | Subject | Re: [PATCH] arm: flush: don't abuse pfn_valid() to check if pfn is in RAM | From | Florian Fainelli <> |
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On 1/31/2024 4:59 AM, Yongqiang Liu wrote: > 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. __sync_icache_dcache() should use > memblock_is_map_memory() instead of pfn_valid() to check if a PFN is in > RAM or not.In Some uio case we will get a crash on a system 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
Humm, what Broadcom platform using a Brahma-B15 CPU are you using out of curiosity?
> 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 > > Fixes: a4d5613c4dc6 ("arm: extend pfn_valid to take into account freed memory map alignment") > Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> > --- > arch/arm/mm/flush.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c > index d19d140a10c7..11ec6c5ff5fc 100644 > --- a/arch/arm/mm/flush.c > +++ b/arch/arm/mm/flush.c > @@ -15,6 +15,7 @@ > #include <asm/smp_plat.h> > #include <asm/tlbflush.h> > #include <linux/hugetlb.h> > +#include <linux/memblock.h> > > #include "mm.h" > > @@ -292,7 +293,7 @@ void __sync_icache_dcache(pte_t pteval) > /* only flush non-aliasing VIPT caches for exec mappings */ > return; > pfn = pte_pfn(pteval); > - if (!pfn_valid(pfn)) > + if (!memblock_is_map_memory(PFN_PHYS(pfn))) > return; > > folio = page_folio(pfn_to_page(pfn));
-- Florian [unhandled content-type:application/pkcs7-signature]
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