• Andrey Smirnov's avatar
    dma-mapping: fix false positivse warnings in dma_common_free_remap() · 2cf2aa6a
    Andrey Smirnov authored
    Commit 5cf45379 ("dma-mapping: introduce a dma_common_find_pages
    helper") changed invalid input check in dma_common_free_remap() from:
    
        if (!area || !area->flags != VM_DMA_COHERENT)
    
    to
    
        if (!area || !area->flags != VM_DMA_COHERENT || !area->pages)
    
    which seem to produce false positives for memory obtained via
    dma_common_contiguous_remap()
    
    This triggers the following warning message when doing "reboot" on ZII
    VF610 Dev Board Rev B:
    
    WARNING: CPU: 0 PID: 1 at kernel/dma/remap.c:112 dma_common_free_remap+0x88/0x8c
    trying to free invalid coherent area: 9ef82980
    Modules linked in:
    CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.3.0-rc6-next-20190820 #119
    Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
    Backtrace:
    [<8010d1ec>] (dump_backtrace) from [<8010d588>] (show_stack+0x20/0x24)
     r7:8015ed78 r6:00000009 r5:00000000 r4:9f4d9b14
    [<8010d568>] (show_stack) from [<8077e3f0>] (dump_stack+0x24/0x28)
    [<8077e3cc>] (dump_stack) from [<801197a0>] (__warn.part.3+0xcc/0xe4)
    [<801196d4>] (__warn.part.3) from [<80119830>] (warn_slowpath_fmt+0x78/0x94)
     r6:00000070 r5:808e540c r4:81c03048
    [<801197bc>] (warn_slowpath_fmt) from [<8015ed78>] (dma_common_free_remap+0x88/0x8c)
     r3:9ef82980 r2:808e53e0
     r7:00001000 r6:a0b1e000 r5:a0b1e000 r4:00001000
    [<8015ecf0>] (dma_common_free_remap) from [<8010fa9c>] (remap_allocator_free+0x60/0x68)
     r5:81c03048 r4:9f4d9b78
    [<8010fa3c>] (remap_allocator_free) from [<801100d0>] (__arm_dma_free.constprop.3+0xf8/0x148)
     r5:81c03048 r4:9ef82900
    [<8010ffd8>] (__arm_dma_free.constprop.3) from [<80110144>] (arm_dma_free+0x24/0x2c)
     r5:9f563410 r4:80110120
    [<80110120>] (arm_dma_free) from [<8015d80c>] (dma_free_attrs+0xa0/0xdc)
    [<8015d76c>] (dma_free_attrs) from [<8020f3e4>] (dma_pool_destroy+0xc0/0x154)
     r8:9efa8860 r7:808f02f0 r6:808f02d0 r5:9ef82880 r4:9ef82780
    [<8020f324>] (dma_pool_destroy) from [<805525d0>] (ehci_mem_cleanup+0x6c/0x150)
     r7:9f563410 r6:9efa8810 r5:00000000 r4:9efd0148
    [<80552564>] (ehci_mem_cleanup) from [<80558e0c>] (ehci_stop+0xac/0xc0)
     r5:9efd0148 r4:9efd0000
    [<80558d60>] (ehci_stop) from [<8053c4bc>] (usb_remove_hcd+0xf4/0x1b0)
     r7:9f563410 r6:9efd0074 r5:81c03048 r4:9efd0000
    [<8053c3c8>] (usb_remove_hcd) from [<8056361c>] (host_stop+0x48/0xb8)
     r7:9f563410 r6:9efd0000 r5:9f5f4040 r4:9f5f5040
    [<805635d4>] (host_stop) from [<80563d0c>] (ci_hdrc_host_destroy+0x34/0x38)
     r7:9f563410 r6:9f5f5040 r5:9efa8800 r4:9f5f4040
    [<80563cd8>] (ci_hdrc_host_destroy) from [<8055ef18>] (ci_hdrc_remove+0x50/0x10c)
    [<8055eec8>] (ci_hdrc_remove) from [<804a2ed8>] (platform_drv_remove+0x34/0x4c)
     r7:9f563410 r6:81c4f99c r5:9efa8810 r4:9efa8810
    [<804a2ea4>] (platform_drv_remove) from [<804a18a8>] (device_release_driver_internal+0xec/0x19c)
     r5:00000000 r4:9efa8810
    [<804a17bc>] (device_release_driver_internal) from [<804a1978>] (device_release_driver+0x20/0x24)
     r7:9f563410 r6:81c41ed0 r5:9efa8810 r4:9f4a1dac
    [<804a1958>] (device_release_driver) from [<804a01b8>] (bus_remove_device+0xdc/0x108)
    [<804a00dc>] (bus_remove_device) from [<8049c204>] (device_del+0x150/0x36c)
     r7:9f563410 r6:81c03048 r5:9efa8854 r4:9efa8810
    [<8049c0b4>] (device_del) from [<804a3368>] (platform_device_del.part.2+0x20/0x84)
     r10:9f563414 r9:809177e0 r8:81cb07dc r7:81c78320 r6:9f563454 r5:9efa8800
     r4:9efa8800
    [<804a3348>] (platform_device_del.part.2) from [<804a3420>] (platform_device_unregister+0x28/0x34)
     r5:9f563400 r4:9efa8800
    [<804a33f8>] (platform_device_unregister) from [<8055dce0>] (ci_hdrc_remove_device+0x1c/0x30)
     r5:9f563400 r4:00000001
    [<8055dcc4>] (ci_hdrc_remove_device) from [<805652ac>] (ci_hdrc_imx_remove+0x38/0x118)
     r7:81c78320 r6:9f563454 r5:9f563410 r4:9f541010
    [<8056538c>] (ci_hdrc_imx_shutdown) from [<804a2970>] (platform_drv_shutdown+0x2c/0x30)
    [<804a2944>] (platform_drv_shutdown) from [<8049e4fc>] (device_shutdown+0x158/0x1f0)
    [<8049e3a4>] (device_shutdown) from [<8013ac80>] (kernel_restart_prepare+0x44/0x48)
     r10:00000058 r9:9f4d8000 r8:fee1dead r7:379ce700 r6:81c0b280 r5:81c03048
     r4:00000000
    [<8013ac3c>] (kernel_restart_prepare) from [<8013ad14>] (kernel_restart+0x1c/0x60)
    [<8013acf8>] (kernel_restart) from [<8013af84>] (__do_sys_reboot+0xe0/0x1d8)
     r5:81c03048 r4:00000000
    [<8013aea4>] (__do_sys_reboot) from [<8013b0ec>] (sys_reboot+0x18/0x1c)
     r8:80101204 r7:00000058 r6:00000000 r5:00000000 r4:00000000
    [<8013b0d4>] (sys_reboot) from [<80101000>] (ret_fast_syscall+0x0/0x54)
    Exception stack(0x9f4d9fa8 to 0x9f4d9ff0)
    9fa0:                   00000000 00000000 fee1dead 28121969 01234567 379ce700
    9fc0: 00000000 00000000 00000000 00000058 00000000 00000000 00000000 00016d04
    9fe0: 00028e0c 7ec87c64 000135ec 76c1f410
    
    Restore original invalid input check in dma_common_free_remap() to
    avoid this problem.
    
    Fixes: 5cf45379 ("dma-mapping: introduce a dma_common_find_pages helper")
    Signed-off-by: default avatarAndrey Smirnov <andrew.smirnov@gmail.com>
    [hch: just revert the offending hunk instead of creating a new helper]
    Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
    2cf2aa6a
remap.c 6.18 KB