1. 11 Mar, 2024 1 commit
    • Yongqiang Liu's avatar
      ARM: 9359/1: flush: check if the folio is reserved for no-mapping addresses · 0c66c6f4
      Yongqiang Liu authored
      Since commit a4d5613c ("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: a4d5613c ("arm: extend pfn_valid to take into account freed memory map alignment")
      Suggested-by: default avatarMike Rapoport <rppt@linux.ibm.com>
      Signed-off-by: default avatarYongqiang Liu <liuyongqiang13@huawei.com>
      Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
      0c66c6f4
  2. 21 Jan, 2024 39 commits