[PATCH v2 2/2] iommu/omap: fix NULL pointer dereference
Ohad Ben-Cohen
ohad at wizery.com
Wed Feb 22 04:14:46 EST 2012
Fix this:
root at omap4430-panda:~# cat /debug/iommu/ducati/mem
[ 62.725708] Unable to handle kernel NULL pointer dereference at virtual addre
ss 0000001c
[ 62.725708] pgd = e6240000
[ 62.737091] [0000001c] *pgd=a7168831, *pte=00000000, *ppte=00000000
[ 62.743682] Internal error: Oops: 17 [#1] SMP
[ 62.743682] Modules linked in: omap_iommu_debug omap_iovmm virtio_rpmsg_bus o
map_remoteproc remoteproc virtio_ring virtio mailbox_mach mailbox
[ 62.743682] CPU: 0 Not tainted (3.3.0-rc1-00265-g382f84e-dirty #682)
[ 62.743682] PC is at debug_read_mem+0x5c/0xac [omap_iommu_debug]
[ 62.743682] LR is at 0x1004
[ 62.777832] pc : [<bf033178>] lr : [<00001004>] psr: 60000013
[ 62.777832] sp : e72c7f40 ip : c0763c00 fp : 00000001
[ 62.777832] r10: 00000000 r9 : 00000000 r8 : e72c7f80
[ 62.777832] r7 : e6ffdc08 r6 : bed1ac78 r5 : 00001000 r4 : e7276000
[ 62.777832] r3 : e60f3460 r2 : 00000000 r1 : e60f38c0 r0 : 00000000
[ 62.777832] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 62.816375] Control: 10c53c7d Table: a624004a DAC: 00000015
[ 62.816375] Process cat (pid: 1176, stack limit = 0xe72c62f8)
[ 62.828369] Stack: (0xe72c7f40 to 0xe72c8000)
...
[ 62.884185] [<bf033178>] (debug_read_mem+0x5c/0xac [omap_iommu_debug]) from [
<c010e354>] (vfs_read+0xac/0x130)
[ 62.884185] [<c010e354>] (vfs_read+0xac/0x130) from [<c010e4a8>] (sys_read+0x
40/0x70)
[ 62.884185] [<c010e4a8>] (sys_read+0x40/0x70) from [<c0014a00>] (ret_fast_sys
call+0x0/0x3c)
Fix also its 'echo bla > /debug/iommu/ducati/mem' Oops sibling, too.
Signed-off-by: Ohad Ben-Cohen <ohad at wizery.com>
Cc: Tony Lindgren <tony at atomide.com>
Cc: Hiroshi Doyu <hdoyu at nvidia.com>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: Russell King <linux at arm.linux.org.uk>
Cc: Joerg Roedel <Joerg.Roedel at amd.com>
---
v2: omap_find_iovm_area only returns NULL for errors. thanks, rmk.
drivers/iommu/omap-iommu-debug.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/omap-iommu-debug.c b/drivers/iommu/omap-iommu-debug.c
index bad9f9d..103dbd9 100644
--- a/drivers/iommu/omap-iommu-debug.c
+++ b/drivers/iommu/omap-iommu-debug.c
@@ -274,7 +274,7 @@ static ssize_t debug_read_mem(struct file *file, char __user *userbuf,
mutex_lock(&iommu_debug_lock);
area = omap_find_iovm_area(dev, (u32)ppos);
- if (IS_ERR(area)) {
+ if (!area) {
bytes = -EINVAL;
goto err_out;
}
@@ -311,7 +311,7 @@ static ssize_t debug_write_mem(struct file *file, const char __user *userbuf,
}
area = omap_find_iovm_area(dev, (u32)ppos);
- if (IS_ERR(area)) {
+ if (!area) {
count = -EINVAL;
goto err_out;
}
--
1.7.5.4
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