Skip to contentSkip to conversation

New: [REGRESSION][BISECTED] Bluetooth broken on MBP and kernel NULL pointer dereference

Bug 202963 [email protected] 1 participant 5 messages Mar 18, 2019 – Apr 27, 2019 Bluetooth drivers

lore
Share & tools
lore

[email protected]

author
#0 lore raw

https://bugzilla.kernel.org/show_bug.cgi?id=202963

            Bug ID: 202963
           Summary: [REGRESSION][BISECTED] Bluetooth broken on MBP and
                    kernel NULL pointer dereference
           Product: Drivers
           Version: 2.5
    Kernel Version: 5.0.2
          Hardware: Intel
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: Bluetooth
          Assignee: [email protected]
          Reporter: [email protected]
        Regression: No

Hardware: Apple MacBook Pro 13,3

As of kernel 5.0 bluetooth is not working anymore and there are a couple null pointer deference bugs in the dmesg during boot (this also delays boot and shutdown by several minutes). The issue has been bisected down to commit 75d11676dccb643de1e850c8a29f5e9aa58157c0 (Bluetooth: hci_bcm: Add support for regulator supplies). Further investigation shows the reason why: at the top of bcm_get_resources() processing is short-circuited on apple machines, and hence dev->supplies is never initialized; this then eventually leads to the null pointer after bcm_gpio_set_power() calls regulator_bulk_enable().

Two obvious fixes I see are:
1. don't call regulator_bulk_enable() if dev->supplies is not initialized
2. initialize dev->supplies on apple machines too

For reference the BUG in dmesg is:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000088
  #PF error: [normal kernel read fault]
  PGD 0 P4D 0 
  Oops: 0000 [#1] SMP PTI
  CPU: 2 PID: 439 Comm: kworker/u16:2 Tainted: G        W  OE     5.0.2+ #4
  Hardware name: Apple Inc. MacBookPro13,3/Mac-A5C67F76ED83108C, BIOS
251.0.0.0.0 10/>
  Workqueue: events_unbound async_run_entry_fn
  RIP: 0010:regulator_enable+0xe/0xc0
  Code: ac ff 8b 43 0c e9 e2 fe ff ff e9 98 22 00 00 66 66 2e 0f 1f 84 00 00 00

00 00>
RSP: 0018:ffffa8f1c25cfd98 EFLAGS: 00010282
RAX: ffffffffac63bef0 RBX: ffff926c1eda6ec8 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000001 R09: 00000000001e1f80
R10: 00000010213103a9 R11: ffffffffae650180 R12: ffff926c2d812000
R13: ffff926c2d859b00 R14: 0000000000000000 R15: ffff926c21a4a6e8
FS: 0000000000000000(0000) GS:ffff926c2e000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000088 CR3: 000000016b616004 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

  Call Trace:
   ? sched_clock+0x5/0x10
   ? process_one_work+0x1ca/0x5f0
   ? __lock_is_held+0x5a/0xa0
   regulator_bulk_enable_async+0x12/0x20
   async_run_entry_fn+0x39/0x160
   process_one_work+0x24c/0x5f0
   worker_thread+0x3c/0x390
   ? process_one_work+0x5f0/0x5f0
   kthread+0x120/0x140
   ? kthread_create_on_node+0x60/0x60
   ret_from_fork+0x3a/0x50
  Modules linked in: acpi_cpufreq(E-) x86_pkg_temp_thermal(E) brcmfmac(E)

intel_power>
CR2: 0000000000000088

regulator_enable+0xe is this line (i.e. regulator is null):

        struct regulator_dev *rdev = regulator->rdev;
Signature · 2 lines
You are receiving this mail because:
You are the assignee for the bug.
author
#2 lore raw

[Bug 202963] [REGRESSION][BISECTED] Bluetooth broken on MBP and kernel NULL pointer dereference

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=202963

[email protected] changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |[email protected]

--- Comment #1 from [email protected] ---
Created attachment 281967
--> https://bugzilla.kernel.org/attachment.cgi?id=281967&action=edit
remove call regulator_bulk_enable() in bcm_gpio_set_power()

Signature · 2 lines
You are receiving this mail because:
You are the assignee for the bug.
author
#3 lore raw

[Bug 202963] [REGRESSION][BISECTED] Bluetooth broken on MBP and kernel NULL pointer dereference

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=202963

--- Comment #2 from Ronald ([email protected]) ---
Btw., I tested https://lkml.org/lkml/2019/3/31/344 and that fixes the issue.

Also, since this is a regression in 5.0, it would be nice to get this backported to 5.0 stable (and 5.1 in case it doesn't make it in there for release).

Signature · 2 lines
You are receiving this mail because:
You are the assignee for the bug.
author
#4 lore raw

[Bug 202963] [REGRESSION][BISECTED] Bluetooth broken on MBP and kernel NULL pointer dereference

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=202963

--- Comment #3 from Ronald ([email protected]) --- (In reply to Ronald from comment #2)

Quoted 1 line

Btw., I tested https://lkml.org/lkml/2019/3/31/344 and that fixes the issue.

Forgot to add: more confirmations that this fixes the issue can be found at
https://github.com/Dunedan/mbp-2016-linux/issues/97#issuecomment-482865366

Signature · 2 lines
You are receiving this mail because:
You are the assignee for the bug.