pkg/report: stop using questionable frames

Most likely reports without proper stack traces were caused by a bug in the
unwinder and are now fixed in 187b96db5ca7 "x86/unwind/orc: Fix
unwind_get_return_address_ptr() for inactive tasks".

Disable trying to use questionable frames for now.

Fixes #1834

8 files changed, 68 insertions, 7 deletions

diff --git a/pkg/report/linux.go b/pkg/report/linux.go
index 7f65bf3bc..d5dac95f5 100644
--- a/pkg/report/linux.go
+++ b/pkg/report/linux.go
@@ -163,13 +163,23 @@ func (ctx *linux) Parse(output []byte) *Report {
 			rep.Corrupted, rep.CorruptedReason = ctx.isCorrupted(title, report, format)
 		}
 		if rep.CorruptedReason == corruptedNoFrames && context != contextConsole && !questionable {
+			// We used to look at questionable frame with the following incentive:
+			// """
 			// Some crash reports have all frames questionable.
 			// So if we get a corrupted report because there are no frames,
 			// try again now looking at questionable frames.
 			// Only do this if we have a real context (CONFIG_PRINTK_CALLER=y),
 			// to be on the safer side. Without context it's too easy to use
 			// a stray frame from a wrong context.
-			continue
+			// """
+			// Most likely reports without proper stack traces were caused by a bug
+			// in the unwinder and are now fixed in 187b96db5ca7 "x86/unwind/orc:
+			// Fix unwind_get_return_address_ptr() for inactive tasks".
+			// Disable trying to use questionable frames for now.
+			useQuestionableFrames := false
+			if useQuestionableFrames {
+				continue
+			}
 		}
 		return rep
 	}
diff --git a/pkg/report/testdata/linux/report/479 b/pkg/report/testdata/linux/report/479
index 6c6166647..af5e68904 100644
--- a/pkg/report/testdata/linux/report/479
+++ b/pkg/report/testdata/linux/report/479
@@ -1,4 +1,5 @@
-TITLE: BUG: unable to handle kernel paging request in nf_tables_newflowtable
+TITLE: BUG: unable to handle kernel paging request in corrupted
+CORRUPTED: Y
 
 [  490.564553][T16898] BUG: unable to handle page fault for address: 0000000000ffff88
 [  490.572415][T16898] #PF: supervisor read access in kernel mode
diff --git a/pkg/report/testdata/linux/report/480 b/pkg/report/testdata/linux/report/480
index 4afe4cd49..7c576902e 100644
--- a/pkg/report/testdata/linux/report/480
+++ b/pkg/report/testdata/linux/report/480
@@ -1,4 +1,5 @@
-TITLE: BUG: unable to handle kernel NULL pointer dereference in handle_external_interrupt_irqoff
+TITLE: BUG: unable to handle kernel NULL pointer dereference in corrupted
+CORRUPTED: Y
 
 [  202.652969][ T9969] BUG: kernel NULL pointer dereference, address: 0000000000000086
 [  202.660811][ T9969] #PF: supervisor instruction fetch in kernel mode
diff --git a/pkg/report/testdata/linux/report/481 b/pkg/report/testdata/linux/report/481
index 26c293e62..e63c33082 100644
--- a/pkg/report/testdata/linux/report/481
+++ b/pkg/report/testdata/linux/report/481
@@ -1,4 +1,5 @@
-TITLE: BUG: unable to handle kernel NULL pointer dereference in handle_external_interrupt_irqoff
+TITLE: BUG: unable to handle kernel NULL pointer dereference in corrupted
+CORRUPTED: Y
 
 [  418.945118][T17277] BUG: kernel NULL pointer dereference, address: 0000000000000086
 [  418.953273][T17277] #PF: supervisor instruction fetch in kernel mode
diff --git a/pkg/report/testdata/linux/report/484 b/pkg/report/testdata/linux/report/484
index 50a101c09..7e2ba4ef2 100644
--- a/pkg/report/testdata/linux/report/484
+++ b/pkg/report/testdata/linux/report/484
@@ -1,5 +1,6 @@
-TITLE: INFO: task hung in register_netdevice_notifier
+TITLE: INFO: task hung in corrupted
 TYPE: HANG
+CORRUPTED: Y
 
 [ 1353.547242][ T1145] INFO: task syz-executor.5:9850 blocked for more than 143 seconds.
 [ 1353.555551][ T1145]       Not tainted 5.7.0-rc5-syzkaller #0
diff --git a/pkg/report/testdata/linux/report/485 b/pkg/report/testdata/linux/report/485
index ce61897e2..5153247c4 100644
--- a/pkg/report/testdata/linux/report/485
+++ b/pkg/report/testdata/linux/report/485
@@ -1,5 +1,6 @@
-TITLE: INFO: task hung in register_netdevice_notifier
+TITLE: INFO: task hung in corrupted
 TYPE: HANG
+CORRUPTED: Y
 
 [  637.252691][ T1136] INFO: task syz-executor.3:20434 blocked for more than 143 seconds.
 [  637.260866][ T1136]       Not tainted 5.7.0-rc5-syzkaller #0
diff --git a/pkg/report/testdata/linux/report/487 b/pkg/report/testdata/linux/report/487
index 5dd962307..fc881f720 100644
--- a/pkg/report/testdata/linux/report/487
+++ b/pkg/report/testdata/linux/report/487
@@ -1,5 +1,6 @@
-TITLE: INFO: rcu detected stall in batadv_mcast_get_bridge
+TITLE: INFO: rcu detected stall in corrupted
 TYPE: HANG
+CORRUPTED: Y
 
 [  463.512820][   T27] audit: type=1326 audit(1589206749.923:16): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=16576 comm="syz-executor.5" exe="/root/syz-executor.5" sig=9 arch=c000003e syscall=228 compat=0 ip=0x45f66a code=0x0
 [  568.528728][    C1] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
diff --git a/pkg/report/testdata/linux/report/500 b/pkg/report/testdata/linux/report/500
new file mode 100644
index 000000000..357006c07
--- /dev/null
+++ b/pkg/report/testdata/linux/report/500
@@ -0,0 +1,45 @@
+TITLE: WARNING in corrupted/usb_submit_urb
+CORRUPTED: Y
+
+Warning: Permanently added '10.128.0.242' (ECDSA) to the list of known hosts.
+syzkaller login: [   30.021137][   T81] usb 1-1: new high-speed USB device number 2 using dummy_hcd
+[   30.110942][   T81] usb 1-1: Using ep0 maxpacket: 16
+[   30.230812][   T81] usb 1-1: config 0 interface 0 altsetting 0 endpoint 0x8D has an invalid bInterval 0, changing to 7
+[   30.241979][   T81] usb 1-1: config 0 interface 0 altsetting 0 bulk endpoint 0x3 has invalid maxpacket 1
+[   30.410779][   T81] usb 1-1: New USB device found, idVendor=0bc7, idProduct=0006, bcdDevice=cb.33
+[   30.419944][   T81] usb 1-1: New USB device strings: Mfr=105, Product=50, SerialNumber=129
+[   30.428482][   T81] usb 1-1: Product: syz
+[   30.432717][   T81] usb 1-1: Manufacturer: syz
+[   30.437319][   T81] usb 1-1: SerialNumber: syz
+[   30.443749][   T81] usb 1-1: config 0 descriptor??
+[   30.460954][ T1791] raw-gadget gadget: fail, usb_ep_enable returned -22
+[   30.482411][   T81] ati_remote 1-1:0.0: Unknown Medion X10 receiver, using default ati_remote Medion keymap
+[   30.492495][   T81] ------------[ cut here ]------------
+[   30.497980][   T81] usb 1-1: BOGUS urb xfer, pipe 1 != type 3
+[   30.504146][   T81] WARNING: CPU: 1 PID: 81 at drivers/usb/core/urb.c:478 usb_submit_urb+0x1188/0x1460
+[   30.515546][   T81] Kernel panic - not syncing: panic_on_warn set ...
+[   30.522138][   T81] CPU: 1 PID: 81 Comm: kworker/1:1 Not tainted 5.6.0-rc3-syzkaller #0
+[   30.530285][   T81] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
+[   30.540419][   T81] Workqueue: usb_hub_wq hub_event
+[   30.545447][   T81] Call Trace:
+[   30.548741][   T81]  dump_stack+0xef/0x16e
+[   30.552986][   T81]  ? usb_submit_urb+0x1090/0x1460
+[   30.558010][   T81]  panic+0x2aa/0x6e1
+[   30.561902][   T81]  ? add_taint.cold+0x16/0x16
+[   30.566630][   T81]  ? __probe_kernel_read+0x188/0x1d0
+[   30.571909][   T81]  ? __warn.cold+0x14/0x30
+[   30.576356][   T81]  ? __warn+0xd5/0x1c8
+[   30.580430][   T81]  ? usb_submit_urb+0x1188/0x1460
+[   30.585489][   T81]  __warn.cold+0x2f/0x30
+[   30.589981][   T81]  ? usb_submit_urb+0x1188/0x1460
+[   30.595057][   T81]  report_bug+0x27b/0x2f0
+[   30.599377][   T81]  do_error_trap+0x12b/0x1e0
+[   30.603968][   T81]  ? usb_submit_urb+0x1188/0x1460
+[   30.608999][   T81]  do_invalid_op+0x32/0x40
+[   30.613460][   T81]  ? usb_submit_urb+0x1188/0x1460
+[   30.618485][   T81]  invalid_op+0x23/0x30
+[   30.622635][   T81] RIP: 0010:usb_submit_urb+0x1188/0x1460
+[   30.628261][   T81] Code: 4d 85 ed 74 46 e8 18 ce dd fd 4c 89 f7 e8 d0 5c 17 ff 41 89 d8 44 89 e1 4c 89 ea 48 89 c6 48 c7 c7 e0 e7 3b 86 e8 a0 5f b2 fd <0f> 0b e9 20 f4 ff ff e8 ec cd dd fd 0f 1f 44 00 00 e8 e2 cd dd fd
+[   30.647861][   T81] RSP: 0018:ffff8881d8a0f0b8 EFLAGS: 00010282
+[   30.653924][   T81] RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
+[