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| author | Gavin Shan <gwshan@linux.vnet.ibm.com> | 2016-08-01 17:17:53 +1000 |
|---|---|---|
| committer | Rob Herring <robh@kernel.org> | 2016-08-09 12:36:27 -0500 |
| commit | 89c67752ae4dedc1244344b266c837ddb4053ebd (patch) | |
| tree | ae9005a1f0b5d4ff191da7907da4dc347332bc47 /drivers/of | |
| parent | beab47d55b883e85bec7771a899ac791c6f92c80 (diff) | |
| download | linux-89c67752ae4dedc1244344b266c837ddb4053ebd.tar.gz linux-89c67752ae4dedc1244344b266c837ddb4053ebd.tar.xz | |
drivers/of: Validate device node in __unflatten_device_tree()
@mynodes is set to NULL when __unflatten_device_tree() is called
to unflatten device sub-tree in PCI hot add scenario on PowerPC
PowerNV platform. Marking @mynodes detached unconditionally causes
kernel crash as below backtrace shows:
Unable to handle kernel paging request for data at address 0x00000000
Faulting instruction address: 0xc000000000b26f64
cpu 0x0: Vector: 300 (Data Access) at [c000003fcc7cf740]
pc: c000000000b26f64: __unflatten_device_tree+0xf4/0x190
lr: c000000000b26f40: __unflatten_device_tree+0xd0/0x190
sp: c000003fcc7cf9c0
msr: 900000000280b033
dar: 0
dsisr: 40000000
current = 0xc000003fcc281680
paca = 0xc00000000ff00000 softe: 0 irq_happened: 0x01
pid = 2724, comm = sh
Linux version 4.7.0-gavin-07754-g92a6836 (gwshan@gwshan) (gcc version \
4.9.3 (Buildroot 2016.02-rc2-00093-g5ea3bce) ) #539 SMP Mon Aug 1 \
12:40:29 AEST 2016
enter ? for help
[c000003fcc7cfa50] c000000000b27060 of_fdt_unflatten_tree+0x60/0x90
[c000003fcc7cfaa0] c0000000004c6288 pnv_php_set_slot_power_state+0x118/0x440
[c000003fcc7cfb80] c0000000004c6a10 pnv_php_enable+0xc0/0x170
[c000003fcc7cfbd0] c0000000004c4d80 power_write_file+0xa0/0x190
[c000003fcc7cfc50] c0000000004be93c pci_slot_attr_store+0x3c/0x60
[c000003fcc7cfc70] c0000000002d3fd4 sysfs_kf_write+0x94/0xc0
[c000003fcc7cfcb0] c0000000002d2c30 kernfs_fop_write+0x180/0x260
[c000003fcc7cfd00] c000000000230fe0 __vfs_write+0x40/0x190
[c000003fcc7cfd90] c000000000232278 vfs_write+0xc8/0x240
[c000003fcc7cfde0] c000000000233d90 SyS_write+0x60/0x110
[c000003fcc7cfe30] c000000000009524 system_call+0x38/0x108
This avoids the kernel crash by marking @mynodes detached only when
@mynodes is dereferencing valid device node in __unflatten_device_tree().
Fixes: 1d1bde550ea3 ("of: fdt: mark unflattened tree as detached")
Reported-by: Meng Li <shlimeng@cn.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Diffstat (limited to 'drivers/of')
| -rw-r--r-- | drivers/of/fdt.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 55f1b8391149..085c6389afd1 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -517,7 +517,7 @@ static void *__unflatten_device_tree(const void *blob, pr_warning("End of tree marker overwritten: %08x\n", be32_to_cpup(mem + size)); - if (detached) { + if (detached && mynodes) { of_node_set_flag(*mynodes, OF_DETACHED); pr_debug("unflattened tree is detached\n"); } |