Messages in this thread | | | From | <> | Subject | Re: Regression: memory corruption on Atmel SAMA5D31 | Date | Fri, 4 Mar 2022 16:48:33 +0000 |
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On 3/4/22 14:38, Peter Rosin wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Hi!
Hi, Peter!
> > On 2022-03-04 12:12, Tudor.Ambarus@microchip.com wrote: >> Hi, Peter! >> >> On 3/4/22 12:57, Peter Rosin wrote: >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >>> >>> On 2022-03-04 07:57, Peter Rosin wrote: >>>> On 2022-03-04 04:55, Saravana Kannan wrote: >>>>> On Thu, Mar 3, 2022 at 1:17 AM Peter Rosin <peda@axentia.se> wrote: >>>>>> >>>>>> On 2022-03-03 04:02, Saravana Kannan wrote: >>>>>>> On Wed, Mar 2, 2022 at 4:29 PM Peter Rosin <peda@axentia.se> wrote: >>>>>>>> >>>>>>>> Hi! >>>>>>>> >>>>>>>> I'm seeing a weird problem, and I'd like some help with further >>>>>>>> things to try in order to track down what's going on. I have >>>>>>>> bisected the issue to >>>>>>>> >>>>>>>> f9aa460672c9 ("driver core: Refactor fw_devlink feature") >>>>>>> >>>>>>> I skimmed through your email and I'll read it more closely tomorrow, >>>>>>> but it wasn't clear if you see this on Linus's tip of the tree too. >>>>>>> Asking because of: >>>>>>> https://lore.kernel.org/lkml/20210930085714.2057460-1-yangyingliang@huawei.com/ >>>>>>> >>>>>>> Also, a couple of other data points that _might_ help. Try kernel >>>>>>> command line option fw_devlink=permissive vs fw_devlink=on (I forget >>>>>>> if this was the default by 5.10) vs fw_devlink=off. >>>>>>> >>>>>>> I'm expecting "off" to fix the issue for you. But if permissive vs on >>>>>>> shows a difference driver issues would start becoming a real >>>>>>> possibility. >>>>>>> >>>>>>> -Saravana >>>>>> >>>>>> Thanks for the quick reply! I don't think I tested the very tip of >>>>>> Linus tree before, only latest rc or something like that, but now I >>>>>> have. I.e. >>>>>> >>>>>> 5859a2b19911 ("Merge branch 'ucount-rlimit-fixes-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace") >>>>>> >>>>>> It would have been typical if an issue that existed for a couple of >>>>>> years had been fixed the last few weeks, but alas, no. >>>>>> >>>>>> On that kernel, and with whatever the default fw_devlink value is, the >>>>> >>>>> It's fw_devlink=on by default from at least 5.12-rc4 or so. >>>>> >>>>>> issue is there. It's a bit hard to tell if the incident probability >>>>>> is the same when trying fw_devlink arguments, but roughly so, and I >>>>>> do not have to wait for long to get a bad hash with the first >>>>>> reproducer >>>>>> >>>>>> while :; do cat testfile | sha256sum; done >>>>>> >>>>>> The output is typical: >>>>>> 78464c59faa203413aceb5f75de85bbf4cde64f21b2d0449a2d72cd2aadac2a3 - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> e03c5524ac6d16622b6c43f917aae730bc0793643f461253c4646b860c1a7215 - >>>>>> 1b8db6218f481cb8e4316c26118918359e764cc2c29393fd9ef4f2730274bb00 - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> 7d60bf848911d3b919d26941be33c928c666e9e5666f392d905af2d62d400570 - >>>>>> 212e1fe02c24134857ffb098f1834a2d87c655e0e5b9e08d4929f49a070be97c - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> 7e33e751eb99a0f63b4f7d64b0a24f3306ffaf7c4bc4b27b82e5886c8ea31bc3 - >>>>>> d7a1f08aa9d0374d46d828fc3582f5927e076ff229b38c28089007cd0599c645 - >>>>>> 4fc963b7c7b14df9d669500f7c062bf378ff2751f705bb91eecd20d2f896f6fe - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> 9360d886046c12d983b8bc73dd22302c57b0aafe58215700604fa977b4715fbe - >>>>>> 4f9173f63cb2e13d1470e59e1b5c657f3b0f4f2e9a55ab6facffbb03f34ce04d - >>>>>> >>>>>> Setting fw_devlink=off makes no difference, AFAICT. >>>>> >>>>> By this, I'm assuming you set fw_devlink=off in the kernel command >>>>> line and you still saw the corruption. >>>> >>>> Yes. On a bad kernel it's the same with all of the following kernel >>>> command lines. >>>> >>>> console=ttyS0,115200 rw oops=panic panic=30 fw_devlink=on ip=none root=ubi0:rootfs ubi.mtd=6 rootfstype=ubifs noinitrd mtdparts=atmel_nand:256k(at91bootstrap),384k(barebox),256k@768k(bareboxenv),256k(bareboxenv2),128k@1536k(oftree),5M@2M(kernel),248M@8M(rootfs),-@256M(ovlfs) >>>> >>>> console=ttyS0,115200 rw oops=panic panic=30 fw_devlink=off ip=none root=ubi0:rootfs ubi.mtd=6 rootfstype=ubifs noinitrd mtdparts=atmel_nand:256k(at91bootstrap),384k(barebox),256k@768k(bareboxenv),256k(bareboxenv2),128k@1536k(oftree),5M@2M(kernel),248M@8M(rootfs),-@256M(ovlfs) >>>> >>>> console=ttyS0,115200 rw oops=panic panic=30 fw_devlink=permissive ip=none root=ubi0:rootfs ubi.mtd=6 rootfstype=ubifs noinitrd mtdparts=atmel_nand:256k(at91bootstrap),384k(barebox),256k@768k(bareboxenv),256k(bareboxenv2),128k@1536k(oftree),5M@2M(kernel),248M@8M(rootfs),-@256M(ovlfs) >>>> >>>>> If that's the case, I can't see how this could possibly have anything >>>>> to do with: >>>>> f9aa460672c9 ("driver core: Refactor fw_devlink feature") >>>>> >>>>> If you look at fw_devlink_link_device(), you'll see that the function >>>>> is NOP if fw_devlink=off (the !fw_devlink_flags check). And from >>>>> there, the rest of the code in the series doesn't run because more >>>>> fields wouldn't get set, etc. That pretty much disables ALL the code >>>>> in the entire series. The only remaining diff would be header file >>>>> changes where I add/remove fields. But that's unlikely to cause any >>>>> issues here because I'm either deleting fields that aren't used or >>>>> adding fields that won't be used (with fw_devlink=off). I think the >>>>> patch was just causing enough timing changes that it's masking the >>>>> real issue. >>>> >>>> When I compare fw_devlink_link_device() from before and after >>>> f9aa460672c9 ("driver core: Refactor fw_devlink feature") >>>> I notice that you also removed an unconditional call to >>>> device_link_add_missing_supplier_links() that was live before, >>>> regardless of any fw_devlink parameter. >>>> >>>> I don't know if that's relevant. Is it? >>>> >>>> Not knowing this code at all, and without any serious attempt >>>> at reading it, from here the comment of that removed function >>>> sure looks like it might cause a different ordering before and >>>> after the patch that is not restored with any fw_devlink >>>> argument. >>> >>> It appears that the device_link_add_missing_supplier_links() difference >>> is not relevant after all. What actually happened in the header file in >>> the "bad" commit was that two fields were removed (none added). Like so: >>> >>> struct dev_links_info { >>> struct list_head suppliers; >>> struct list_head consumers; >>> - struct list_head needs_suppliers; >>> struct list_head defer_sync; >>> - bool need_for_probe; >>> enum dl_dev_state status; >>> }; >>> >>> If I restore those fields on a bad kernel, the issue is no longer >>> visible. That is true for the first bad kernel, i.e. >>> >>> f9aa460672c9 ("driver core: Refactor fw_devlink feature") >>> >>> and for tip of Linus as of recently, i.e. >>> >>> 5859a2b19911 ("Merge branch 'ucount-rlimit-fixes-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace") >>> >>> Which is of course insane and a whole different level of bad. WTF!?! >>> >>> I wonder if I can dig out the old SAMA5D31 evaluation kit and reproduce >>> there? I think that's next on the list... >>> >> >> I have a sama5d3_xplained that uses a SAMA5D36 and has a 256MBytes DDR2 and a >> 256MBytes NAND Flash. I tried a test with a 200MB file, rootfs on sdcard and >> I couldn't reproduce the bug. I'm using Linus's latest kernel: >> 38f80f42147f (HEAD, origin/master, origin/HEAD) MAINTAINERS: Remove dead patchwork link >> >> root@sama5d3-xplained-sd:~# dd if=/dev/urandom of=testfile bs=1024 count=200000 >> 200000+0 records in >> 200000+0 records out >> 204800000 bytes (205 MB, 195 MiB) copied, 37.6424 s, 5.4 MB/s >> root@sama5d3-xplained-sd:~# for i in 1 2 3 4 5 6 7 8; do cat testfile | sha256sum; done >> 2a4f1534aec6ace9d68f2f42fa28c1f1fe7bd281f960f2218797557aa41fe8de - >> 2a4f1534aec6ace9d68f2f42fa28c1f1fe7bd281f960f2218797557aa41fe8de - >> 2a4f1534aec6ace9d68f2f42fa28c1f1fe7bd281f960f2218797557aa41fe8de - >> 2a4f1534aec6ace9d68f2f42fa28c1f1fe7bd281f960f2218797557aa41fe8de - >> 2a4f1534aec6ace9d68f2f42fa28c1f1fe7bd281f960f2218797557aa41fe8de - >> 2a4f1534aec6ace9d68f2f42fa28c1f1fe7bd281f960f2218797557aa41fe8de - >> 2a4f1534aec6ace9d68f2f42fa28c1f1fe7bd281f960f2218797557aa41fe8de - >> 2a4f1534aec6ace9d68f2f42fa28c1f1fe7bd281f960f2218797557aa41fe8de - >> root@sama5d3-xplained-sd:~# >> >> I'll put the rootfs on NAND and try to retest. Maybe to do some other tests >> in parallel to have more interrupts on the system. Will let you know if I can >> reproduce the bug on sama5d3_xplained. > > Thanks for testing!
you're welcome, no worries. > > Since you (probably) don't have the interrupt source from the USB > serial chip that I have, that is not completely unexpected. > > $ lsusb > Bus 001 Device 002: ID 0403:6011 Future Technology Devices International, Ltd FT4232H Quad HS USB-UART/FIFO IC > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub > $ cat /sys/bus/usb-serial/devices/ttyUSB?/latency_timer > 1 > 1 > 1 > 1 > > Also, your file is perhaps too small? You leave approx 50MB for the > system, so it might be the case that the page cache can hold the whole > file? > > So, can you please try that again with a slightly bigger file or if you > restrict how much RAM you allow the kernel to see? > > And if you don't have the FTDI usb-serial chip, you should probably go > with the other reproducer, namely to simply copy the random file to a > different host using scp.
I kept the rootfs on sdcard but this time I generated a 300MB random file. I ran a mtd_stresstest on the NAND flash while doing the sha256sum or scp tests. All went fine.
Here's the mtd_stresstest being successful https://pastebin.com/eWQNHAsE While the stresstest was running I did the following sha256 and scp tests: https://pastebin.com/wjutw63C
On my laptop the sha256sum is matching the one on the board: $ sha256sum /tmp/testfile? d9232cee3ac29c3a9aaff8b23b4cb2914edd54e21550a555656988596fbd0b58 /tmp/testfile1 d9232cee3ac29c3a9aaff8b23b4cb2914edd54e21550a555656988596fbd0b58 /tmp/testfile2 d9232cee3ac29c3a9aaff8b23b4cb2914edd54e21550a555656988596fbd0b58 /tmp/testfile3 d9232cee3ac29c3a9aaff8b23b4cb2914edd54e21550a555656988596fbd0b58 /tmp/testfile4 d9232cee3ac29c3a9aaff8b23b4cb2914edd54e21550a555656988596fbd0b58 /tmp/testfile5 d9232cee3ac29c3a9aaff8b23b4cb2914edd54e21550a555656988596fbd0b58 /tmp/testfile6 d9232cee3ac29c3a9aaff8b23b4cb2914edd54e21550a555656988596fbd0b58 /tmp/testfile7 d9232cee3ac29c3a9aaff8b23b4cb2914edd54e21550a555656988596fbd0b58 /tmp/testfile8
Here's what "top" cmd was showing when doing the scp and the mtd_stresstest: top - 14:40:13 up 39 min, 3 users, load average: 1.95, 1.88, 1.80 Tasks: 54 total, 3 running, 51 sleeping, 0 stopped, 0 zombie %Cpu(s): 35.1 us, 48.1 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 16.9 si, 0.0 st MiB Mem : 242.3 total, 2.5 free, 15.2 used, 224.6 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 220.1 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 464 root 20 0 4296 3292 2940 R 46.6 1.3 0:17.53 ssh 401 root 20 0 1668 760 676 R 45.0 0.3 17:57.11 modprobe 463 root 20 0 3456 2232 2000 S 5.2 0.9 0:02.04 scp
Here's what "top" cmd was showing when doing the sha256sum and the mtd_stresstest: top - 14:12:47 up 12 min, 3 users, load average: 2.14, 1.92, 1.08 Tasks: 54 total, 3 running, 51 sleeping, 0 stopped, 0 zombie %Cpu(s): 37.4 us, 58.4 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 4.2 si, 0.0 st MiB Mem : 242.3 total, 3.0 free, 14.8 used, 224.5 buff/cache MiB Swap: 0.0 total, 0.0 free, 0.0 used. 220.6 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 420 root 20 0 1396 784 692 R 47.2 0.3 0:06.42 sha256sum 401 root 20 0 1668 1208 1124 R 43.0 0.5 4:50.34 modprobe 419 root 20 0 1520 868 680 S 6.5 0.3 0:00.92 cat
Peter, do you think it is worth to do some other tests on sama5d3_xplained? I'll try to find a SAMA5D31 evaluation kit meanwhile.
Cheers, ta
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