Re: null pointer dereference in omap_wdt

[Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>]

On 11/01/2015 03:11 PM, Peter Robinson wrote:
> Hi Lars,
>
> I'm seeing the following crash in omap_wdt in omap_wdt_get_timeleft
> when I just run wdctl on a couple of different TI devices, the
> beaglebone black/green or panda ES. I'm seeing it on both 4.2.3 and
> 4.3rc7, looking at git it looks like you added the fuction in June,
> have you seen this on any of your platforms?
>

I think that
	struct omap_wdt_dev *wdev = watchdog_get_drvdata(wdog);
in omap_wdt_get_timeleft() needs to be
	struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);

Looks like there was an overlap between commit d2f78268ba58 ("watchdog:
omap: put struct watchdog_device into driver data") and commit 452fafed839e
("watchdog: omap_wdt: implement get_timeleft").

Can someone test this and send a patch to fix the problem ?

Thanks,
Guenter

> Peter
>
> [  299.672508] Unable to handle kernel NULL pointer dereference at
> virtual address 00000088
> [  299.681372] pgd = de35c000
> [  299.684385] [00000088] *pgd=00000000
> [  299.688205] Internal error: Oops: 5 [#1] SMP ARM
> [  299.693086] Modules linked in: ip6t_rpfilter ip6t_REJECT
> nf_reject_ipv6 xt_conntrack ebtable_filter ebtable_nat ebtable_broute
> bridge stp llc ebtables ip6table_mangle ip6table_security ip6table_nat
> nf_conntra
> ck_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_raw ip6table_filter
> ip6_tables iptable_mangle iptable_security iptable_nat
> nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack
> iptable_raw musb_dsps musb_
> hdrc phy_am335x udc_core phy_generic phy_am335x_control cppi41
> omap_aes omap_sham omap_hwspinlock hwspinlock_core omap_rng
> omap_mailbox at24 musb_am335x 8250_omap omap_wdt leds_gpio cpufreq_dt
> smsc davinci_mdio
> mmc_block ti_cpsw cpsw_common ptp pps_core cpsw_ale davinci_cpdma
> omap_hsmmc omap_dma mmc_core i2c_dev
> [  299.761395] CPU: 0 PID: 1242 Comm: wdctl Not tainted
> 4.3.0-0.rc7.git0.1.fc24.armv7hl #1
> [  299.769841] Hardware name: Generic AM33XX (Flattened Device Tree)
> [  299.776280] task: de505b00 ti: dcf26000 task.ti: dcf26000
> [  299.782017] PC is at omap_wdt_get_timeleft+0xc/0x20 [omap_wdt]
> [  299.788205] LR is at watchdog_ioctl+0x3cc/0x42c
> [  299.793001] pc : [<bf09f138>]    lr : [<c0739c54>]    psr: 600f0013
> [  299.793001] sp : dcf27f18  ip : 00000003  fp : 7f626bbe
> [  299.805114] r10: 00000000  r9 : 00000003  r8 : becb1ab8
> [  299.810634] r7 : dbc0837c  r6 : dbc08318  r5 : becb1ab8  r4 : 00000000
> [  299.817526] r3 : 00000000  r2 : 00000000  r1 : 8004570a  r0 : dbc08318
> [  299.824423] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> [  299.831958] Control: 10c5387d  Table: 9e35c019  DAC: 00000051
> [  299.838026] Process wdctl (pid: 1242, stack limit = 0xdcf26220)
> [  299.844280] Stack: (0xdcf27f18 to 0xdcf28000)
> [  299.848890] 7f00:
>      becb1ab8 dbf241b8
> [  299.857541] 7f20: dc823840 8004570a becb1ab8 c03988a4 dcf27f48
> dcf17100 00000000 de352850
> [  299.866191] 7f40: dde86ee0 0000570a dc82380b dcf27f3c dbf241b8
> 00000020 c0df9250 c0df6c48
> [  299.874840] 7f60: dc823840 8004570a 00000000 dc823840 dc823840
> 8004570a becb1ab8 00000003
> [  299.883489] 7f80: 00000000 c03989d4 becb1b74 7f626bad 00000003
> 00000036 c020fcc4 dcf26000
> [  299.892137] 7fa0: 00000000 c020fb00 becb1b74 7f626bad 00000003
> 8004570a becb1ab8 00000001
> [  299.900786] 7fc0: becb1b74 7f626bad 00000003 00000036 00000001
> 00000000 7f637eb0 7f626bbe
> [  299.909434] 7fe0: 7f637f10 becb1a3c 7f623a54 b6ee5e0c a00f0010
> 00000003 00000000 00000000
> [  299.918136] [<bf09f138>] (omap_wdt_get_timeleft [omap_wdt]) from
> [<c0739c54>] (watchdog_ioctl+0x3cc/0x42c)
> [  299.928365] [<c0739c54>] (watchdog_ioctl) from [<c03988a4>]
> (do_vfs_ioctl+0x5bc/0x698)
> [  299.936747] [<c03988a4>] (do_vfs_ioctl) from [<c03989d4>]
> (SyS_ioctl+0x54/0x7c)
> [  299.944499] [<c03989d4>] (SyS_ioctl) from [<c020fb00>]
> (ret_fast_syscall+0x0/0x3c)
> [  299.952511] Code: e12fff1e e52de004 e8bd4000 e5903060 (e5933088)
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