[PATCH 3.13.y-ckt 092/108] tracing: Fix setting of start_index in find_next()

From	Kamal Mostafa <kamal@canonical.com>
Newsgroups	linux.kernel
Subject	[PATCH 3.13.y-ckt 092/108] tracing: Fix setting of start_index in find_next()
Date	2016-01-23 00:40 +0100
Message-ID	<qTTtb-2G5-83@gated-at.bofh.it> (permalink)
References	<qTTt7-2G5-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

3.13.11-ckt33 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Qiu Peiyang <peiyangx.qiu@intel.com>

commit f36d1be2930ede0a1947686e1126ffda5d5ee1bb upstream.

When we do cat /sys/kernel/debug/tracing/printk_formats, we hit kernel
panic at t_show.

general protection fault: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 2957 Comm: sh Tainted: G W  O 3.14.55-x86_64-01062-gd4acdc7 #2
RIP: 0010:[<ffffffff811375b2>]
 [<ffffffff811375b2>] t_show+0x22/0xe0
RSP: 0000:ffff88002b4ebe80  EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000004
RDX: 0000000000000004 RSI: ffffffff81fd26a6 RDI: ffff880032f9f7b1
RBP: ffff88002b4ebe98 R08: 0000000000001000 R09: 000000000000ffec
R10: 0000000000000000 R11: 000000000000000f R12: ffff880004d9b6c0
R13: 7365725f6d706400 R14: ffff880004d9b6c0 R15: ffffffff82020570
FS:  0000000000000000(0000) GS:ffff88003aa00000(0063) knlGS:00000000f776bc40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f6c02ff0 CR3: 000000002c2b3000 CR4: 00000000001007f0
Call Trace:
 [<ffffffff811dc076>] seq_read+0x2f6/0x3e0
 [<ffffffff811b749b>] vfs_read+0x9b/0x160
 [<ffffffff811b7f69>] SyS_read+0x49/0xb0
 [<ffffffff81a3a4b9>] ia32_do_call+0x13/0x13
 ---[ end trace 5bd9eb630614861e ]---
Kernel panic - not syncing: Fatal exception

When the first time find_next calls find_next_mod_format, it should
iterate the trace_bprintk_fmt_list to find the first print format of
the module. However in current code, start_index is smaller than *pos
at first, and code will not iterate the list. Latter container_of will
get the wrong address with former v, which will cause mod_fmt be a
meaningless object and so is the returned mod_fmt->fmt.

This patch will fix it by correcting the start_index. After fixed,
when the first time calls find_next_mod_format, start_index will be
equal to *pos, and code will iterate the trace_bprintk_fmt_list to
get the right module printk format, so is the returned mod_fmt->fmt.

Link: http://lkml.kernel.org/r/5684B900.9000309@intel.com

Fixes: 102c9323c35a8 "tracing: Add __tracepoint_string() to export string pointers"
Signed-off-by: Qiu Peiyang <peiyangx.qiu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 kernel/trace/trace_printk.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 2900817..7c8cef6 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -269,6 +269,7 @@ static const char **find_next(void *v, loff_t *pos)
 	if (*pos < last_index + start_index)
 		return __start___tracepoint_str + (*pos - last_index);
 
+	start_index += last_index;
 	return find_next_mod_format(start_index, v, fmt, pos);
 }
 
-- 
1.9.1

Thread

[3.13.y-ckt stable] Linux 3.13.11-ckt33 stable review Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 086/108] x86/mce: Ensure offline CPUs don't participate in rendezvous process Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 053/108] xhci: fix usb2 resume timing and races. Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 009/108] sh_eth: fix kernel oops in skb_put() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 093/108] async_tx: use GFP_NOWAIT rather than GFP_IO Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 102/108] pinctrl: bcm2835: Fix initial value for direction_output Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 105/108] qlcnic: fix a timeout loop Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 095/108] ftrace/module: Call clean up function when module init fails early Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 088/108] ALSA: hda/realtek - Fix silent headphone output on MacPro 4,1 (v2) Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 107/108] include/linux/mmdebug.h: should include linux/bug.h Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 090/108] mm/memory_hotplug.c: check for missing sections in test_pages_in_a_zone() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 075/108] xen-netback: use RING_COPY_REQUEST() throughout Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 096/108] vmstat: allocate vmstat_wq before it is used Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 103/108] mISDN: fix a loop count Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 092/108] tracing: Fix setting of start_index in find_next() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 099/108] ipv6/addrlabel: fix ip6addrlbl_get() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 091/108] ftrace/scripts: Fix incorrect use of sprintf in recordmcount Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 077/108] xen-blkback: read from indirect descriptors only once Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:40 +0100
  [PATCH 3.13.y-ckt 057/108] mm, vmstat: allow WQ concurrency to discover memory reclaim doesn't make any progress Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 076/108] xen-blkback: only read request operation from shared ring once Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 050/108] ses: Fix problems with simple enclosures Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 059/108] drivers/base/memory.c: prohibit offlining of memory blocks with missing sections Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 049/108] dm btree: fix bufio buffer leaks in dm_btree_del() error path Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 052/108] ses: fix additional element traversal bug Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 073/108] xen: Add RING_COPY_REQUEST() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 072/108] s390/dis: Fix handling of format specifiers Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 070/108] ARC: dw2 unwind: Ignore CIE version !=1 gracefully instead of bailing Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 045/108] dm space map metadata: fix ref counting bug when bootstrapping a new space map Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 071/108] ALSA: hda - Set SKL+ hda controller power at freeze() and thaw() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 068/108] ftrace/scripts: Have recordmcount copy the object file Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 066/108] spi: fix parent-device reference leak Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 064/108] ALSA: usb-audio: Add a more accurate volume quirk for AudioQuest DragonFly Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 058/108] mm: hugetlb: call huge_pte_alloc() only if ptep is null Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 062/108] tty: Fix GPF in flush_to_ldisc() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 082/108] xen/pciback: For XEN_PCI_OP_disable_msi[|x] only disable if device has MSI(X) enabled. Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 081/108] xen/pciback: Do not install an IRQ handler for MSI interrupts. Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 054/108] USB: add quirk for devices with broken LPM Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 083/108] xen/pciback: Don't allow MSI-X ops if PCI_COMMAND_MEMORY is not set. Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 051/108] vgaarb: fix signal handling in vga_get() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 046/108] ipmi: move timer init to before irq is setup Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 069/108] ARC: dw2 unwind: Reinstante unwinding out of modules Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 074/108] xen-netback: don't use last request to determine minimum Tx credit Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 063/108] genirq: Prevent chip buslock deadlock Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 060/108] sh64: fix __NR_fgetxattr Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 048/108] rfkill: copy the name into the rfkill struct Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 078/108] xen/pciback: Save xen_pci_op commands before processing it Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 079/108] xen/pciback: Return error on XEN_PCI_OP_enable_msi when device has MSI or MSI-X enabled Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 061/108] n_tty: Fix poll() after buffer-limited eof push read Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 056/108] parisc iommu: fix panic due to trying to allocate too large region Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 055/108] powercap / RAPL: fix BIOS lock check Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 080/108] xen/pciback: Return error on XEN_PCI_OP_enable_msix when device has MSI or MSI-X enabled Kamal Mostafa <kamal@canonical.com> - 2016-01-23 00:50 +0100
  [PATCH 3.13.y-ckt 022/108] USB: cdc_acm: Ignore Infineon Flash Loader utility Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 015/108] tools: Add a "make all" rule Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 020/108] iio: fix some warning messages Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 031/108] irqchip/versatile-fpga: Fix PCI IRQ mapping on Versatile PB Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 014/108] KVM: x86: Reload pit counters for all channels when restoring state Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 026/108] drm/ttm: Fixed a read/write lock imbalance Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 023/108] USB: serial: Another Infineon flash loader USB ID Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 042/108] radeon/cik: Fix GFX IB test on Big-Endian Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 025/108] jbd2: Fix unreclaimed pages after truncate in data=journal mode Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 021/108] USB: cp210x: Remove CP2110 ID from compatibility list Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 038/108] ALSA: rme96: Fix unexpected volume reset after rate changes Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 017/108] net: ipmr: fix static mfc/dev leaks on table destruction Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 036/108] SCSI: Fix NULL pointer dereference in runtime PM Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 007/108] ipv6: sctp: clone options to avoid use after free Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 018/108] fuse: break infinite loop in fuse_fill_write_pages() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 041/108] 9p: ->evict_inode() should kick out ->i_data, not ->i_mapping Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 029/108] sata_sil: disable trim Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 040/108] virtio: fix memory leak of virtio ida cache layers Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 010/108] pptp: verify sockaddr_len in pptp_bind() and pptp_connect() Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 043/108] crypto: skcipher - Copy iv from desc even for 0-len walks Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 019/108] usb: gadget: pxa27x: fix suspend callback Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 030/108] staging: lustre: echo_copy.._lsm() dereferences userland pointers directly Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 037/108] usb: xhci: fix config fail of FS hub behind a HS hub with MTT Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 034/108] usb: Use the USB_SS_MULT() macro to decode burst multiplier for log message Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 027/108] i2c: mv64xxx: The n clockdiv factor is 0 based on sunxi SoCs Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 035/108] dm btree: fix leak of bufio-backed block in btree_split_sibling error path Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 033/108] USB: whci-hcd: add check for dma mapping error Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 016/108] efi: Disable interrupts around EFI calls, not in the epilog/prolog calls Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 008/108] net: add validation for the socket syscall protocol argument Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 028/108] AHCI: Fix softreset failed issue of Port Multiplier Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 044/108] dm thin metadata: fix bug when taking a metadata snapshot Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 011/108] bluetooth: Validate socket address length in sco_sock_bind(). Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 012/108] af_unix: Revert 'lock_interruptible' in stream receive code Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:00 +0100
  [PATCH 3.13.y-ckt 005/108] sctp: use the same clock as if sock source timestamps were on Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:10 +0100
  [PATCH 3.13.y-ckt 003/108] gre6: allow to update all parameters via rtnl Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:10 +0100
  [PATCH 3.13.y-ckt 004/108] atl1c: Improve driver not to do order 4 GFP_ATOMIC allocation Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:10 +0100
  [PATCH 3.13.y-ckt 001/108] ARC: Fix silly typo in MAINTAINERS file Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:10 +0100
  [PATCH 3.13.y-ckt 006/108] sctp: update the netstamp_needed counter when copying sockets Kamal Mostafa <kamal@canonical.com> - 2016-01-23 01:10 +0100

csiph-web