Messages in this thread | | | Date | Mon, 12 Feb 2024 10:03:18 +0000 | Subject | Re: [PATCH] comedi: comedi_8255: Correct error in subdevice initialization | From | Ian Abbott <> |
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On 11/02/2024 17:58, Frej Drejhammar wrote: > The refactoring done in commit 5c57b1ccecc7 ("comedi: comedi_8255: Rework > subdevice initialization functions") to the initialization of the io > field of struct subdev_8255_private broke all cards using the > drivers/comedi/drivers/comedi_8255.c module. > > Prior to 5c57b1ccecc7, __subdev_8255_init() initialized the io field > in the newly allocated struct subdev_8255_private to the non-NULL > callback given to the function, otherwise it used a flag parameter to > select between subdev_8255_mmio and subdev_8255_io. The refactoring > removed that logic and the flag, as subdev_8255_mm_init() and > subdev_8255_io_init() now explicitly pass subdev_8255_mmio and > subdev_8255_io respectively to __subdev_8255_init(), only > __subdev_8255_init() never sets spriv->io to the supplied > callback. That spriv->io is NULL leads to a later BUG: > > BUG: kernel NULL pointer dereference, address: 0000000000000000 > PGD 0 P4D 0 > Oops: 0010 [#1] SMP PTI > CPU: 1 PID: 1210 Comm: systemd-udevd Not tainted 6.7.3-x86_64 #1 > Hardware name: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX > RIP: 0010:0x0 > Code: Unable to access opcode bytes at 0xffffffffffffffd6. > RSP: 0018:ffffa3f1c02d7b78 EFLAGS: 00010202 > RAX: 0000000000000000 RBX: ffff91f847aefd00 RCX: 000000000000009b > RDX: 0000000000000003 RSI: 0000000000000001 RDI: ffff91f840f6fc00 > RBP: ffff91f840f6fc00 R08: 0000000000000000 R09: 0000000000000001 > R10: 0000000000000000 R11: 000000000000005f R12: 0000000000000000 > R13: 0000000000000000 R14: ffffffffc0102498 R15: ffff91f847ce6ba8 > FS: 00007f72f4e8f500(0000) GS:ffff91f8d5c80000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffffffffffffd6 CR3: 000000010540e000 CR4: 00000000000406f0 > Call Trace: > <TASK> > ? __die_body+0x15/0x57 > ? page_fault_oops+0x2ef/0x33c > ? insert_vmap_area.constprop.0+0xb6/0xd5 > ? alloc_vmap_area+0x529/0x5ee > ? exc_page_fault+0x15a/0x489 > ? asm_exc_page_fault+0x22/0x30 > __subdev_8255_init+0x79/0x8d [comedi_8255] > pci_8255_auto_attach+0x11a/0x139 [8255_pci] > comedi_auto_config+0xac/0x117 [comedi] > ? __pfx___driver_attach+0x10/0x10 > pci_device_probe+0x88/0xf9 > really_probe+0x101/0x248 > __driver_probe_device+0xbb/0xed > driver_probe_device+0x1a/0x72 > __driver_attach+0xd4/0xed > bus_for_each_dev+0x76/0xb8 > bus_add_driver+0xbe/0x1be > driver_register+0x9a/0xd8 > comedi_pci_driver_register+0x28/0x48 [comedi_pci] > ? __pfx_pci_8255_driver_init+0x10/0x10 [8255_pci] > do_one_initcall+0x72/0x183 > do_init_module+0x5b/0x1e8 > init_module_from_file+0x86/0xac > __do_sys_finit_module+0x151/0x218 > do_syscall_64+0x72/0xdb > entry_SYSCALL_64_after_hwframe+0x6e/0x76 > RIP: 0033:0x7f72f50a0cb9 > Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 47 71 0c 00 f7 d8 64 89 01 48 > RSP: 002b:00007ffd47e512d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 > RAX: ffffffffffffffda RBX: 0000562dd06ae070 RCX: 00007f72f50a0cb9 > RDX: 0000000000000000 RSI: 00007f72f52d32df RDI: 000000000000000e > RBP: 0000000000000000 R08: 00007f72f5168b20 R09: 0000000000000000 > R10: 0000000000000050 R11: 0000000000000246 R12: 00007f72f52d32df > R13: 0000000000020000 R14: 0000562dd06785c0 R15: 0000562dcfd0e9a8 > </TASK> > Modules linked in: 8255_pci(+) comedi_8255 comedi_pci comedi intel_gtt e100(+) acpi_cpufreq rtc_cmos usbhid > CR2: 0000000000000000 > ---[ end trace 0000000000000000 ]--- > RIP: 0010:0x0 > Code: Unable to access opcode bytes at 0xffffffffffffffd6. > RSP: 0018:ffffa3f1c02d7b78 EFLAGS: 00010202 > RAX: 0000000000000000 RBX: ffff91f847aefd00 RCX: 000000000000009b > RDX: 0000000000000003 RSI: 0000000000000001 RDI: ffff91f840f6fc00 > RBP: ffff91f840f6fc00 R08: 0000000000000000 R09: 0000000000000001 > R10: 0000000000000000 R11: 000000000000005f R12: 0000000000000000 > R13: 0000000000000000 R14: ffffffffc0102498 R15: ffff91f847ce6ba8 > FS: 00007f72f4e8f500(0000) GS:ffff91f8d5c80000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffffffffffffd6 CR3: 000000010540e000 CR4: 00000000000406f0 > > This patch simply corrects the above mistake by initializing spriv->io > to the given io callback. > > Fixes: 5c57b1ccecc7 ("comedi: comedi_8255: Rework subdevice initialization functions") > Signed-off-by: Frej Drejhammar <frej.drejhammar@gmail.com> > Cc: <stable@vger.kernel.org> > --- > drivers/comedi/drivers/comedi_8255.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/comedi/drivers/comedi_8255.c b/drivers/comedi/drivers/comedi_8255.c > index e4974b508328..a933ef53845a 100644 > --- a/drivers/comedi/drivers/comedi_8255.c > +++ b/drivers/comedi/drivers/comedi_8255.c > @@ -159,6 +159,7 @@ static int __subdev_8255_init(struct comedi_device *dev, > return -ENOMEM; > > spriv->context = context; > + spriv->io = io; > > s->type = COMEDI_SUBD_DIO; > s->subdev_flags = SDF_READABLE | SDF_WRITABLE;
Thanks for the fix. I screwed up!
Acked-by: Ian Abbott <abbotti@mev.co.uk> Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
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