[lkml]   [2020]   [Jan]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH v1] driver core: Use list_del_init to replace list_del at device_links_purge()
We found that enabling kernel compilation options CONFIG_SCSI_ENCLOSURE and
CONFIG_ENCLOSURE_SERVICES, repeated initialization and deletion of the same
SCSI device will cause system panic, as follows:
[72.425705] Unable to handle kernel paging request at virtual address
[72.595093] Call trace:
[72.597532] device_del + 0x194 / 0x3a0
[72.601012] enclosure_remove_device + 0xbc / 0xf8
[72.605445] ses_intf_remove + 0x9c / 0xd8
[72.609185] device_del + 0xf8 / 0x3a0
[72.612576] device_unregister + 0x14 / 0x30
[72.616489] __scsi_remove_device + 0xf4 / 0x140
[72.620747] scsi_remove_device + 0x28 / 0x40
[72.624745] scsi_remove_target + 0x1c8 / 0x220

After analysis, we see that in the error scenario, the ses module has the
following calling sequence:
device_register() -> device_del() -> device_add() -> device_del().
The first call to device_del() is fine, but the second call to device_del()
will cause a system panic.

Through disassembly, we locate that panic happen when device_links_purge()
call list_del() to remove device_links.needs_suppliers from list, and
list_del() will set this list entry's prev and next pointers to poison.
So if INIT_LIST_HEAD() is not re-executed before the next list_del(), It
will cause the system to access a memory address which is posioned.

Therefore, replace list_del() with list_del_init() can avoid such issue.

Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition")
Signed-off-by: Luo Jiaxing <>
Reviewed-by: John Garry <>
drivers/base/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 42a6724..7b9b0d6 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1103,7 +1103,7 @@ static void device_links_purge(struct device *dev)
struct device_link *link, *ln;

- list_del(&dev->links.needs_suppliers);
+ list_del_init(&dev->links.needs_suppliers);

 \ /
  Last update: 2020-01-08 12:35    [W:0.077 / U:5.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site