This is a patchset rebased to the latest Jens linux-block tree,
for-3.13/core branch to 1) protect blk_get_request __GFP_WAIT callers
from dead queues and then 2) convert blk_get_request to return ERR_PTR
to distinguish between dead queues and low-memory scenarios [1]. A
similar bug report appeared on LKML in June [2], as well as Red Hat
bugzilla #975287.
>From the RHBZ, Paolo Bonzini provided me an easy repro program via
fellow Red Hat customer. The bug reporter said:
1. Connect a USB CD drive to the server. (It will be recognized as /dev/sr1.)
2. Run the following program with gdb, and break on line 11.
1 #include <stdio.h>
2 #include <unistd.h>
3 #include <sys/ioctl.h>
4 #include <fcntl.h>
5 #include <linux/cdrom.h>
6
7 int main(int argc, char *argv[])
8 {
9 int fd;
10 if ((fd = open("/dev/sr1", O_RDONLY | O_NONBLOCK)) < 0)
perror("open");
11 if (ioctl(fd, CDROMEJECT, 0) < 0) perror("ioctl");
12 close(fd);
13 return(0);
14 }
3. Disconnect the USB CD drive.
4. Continue to execute the program. Then, kernel panic occurs.
I verified the repro with an unpatched for-3.13/core kernel. When
testing with the patchset, the ioctl fails and returns ENODEV.
Changes from v6:
- rebase to latest linux-block, for-3.13/core branch
- provide bug repro
Regards,
[1] http://thread.gmane.org/gmane.linux.scsi/80934
[2] http://thread.gmane.org/gmane.linux.kernel/1502882
Joe Lawrence (2):
block,scsi: verify return pointer from blk_get_request
block,scsi: convert and handle ERR_PTR from blk_get_request
block/blk-core.c | 34 ++++++++++++++---------------
block/bsg.c | 8 +++----
block/scsi_ioctl.c | 13 ++++++++---
drivers/block/paride/pd.c | 2 ++
drivers/block/pktcdvd.c | 2 ++
drivers/block/sx8.c | 2 +-
drivers/cdrom/cdrom.c | 4 ++--
drivers/ide/ide-park.c | 2 +-
drivers/scsi/device_handler/scsi_dh_alua.c | 2 +-
drivers/scsi/device_handler/scsi_dh_emc.c | 2 +-
drivers/scsi/device_handler/scsi_dh_hp_sw.c | 4 ++--
drivers/scsi/device_handler/scsi_dh_rdac.c | 2 +-
drivers/scsi/osd/osd_initiator.c | 4 ++--
drivers/scsi/osst.c | 2 +-
drivers/scsi/scsi_error.c | 2 ++
drivers/scsi/scsi_lib.c | 2 +-
drivers/scsi/scsi_tgt_lib.c | 2 +-
drivers/scsi/sg.c | 4 ++--
drivers/scsi/st.c | 2 +-
drivers/target/target_core_pscsi.c | 2 +-
20 files changed, 55 insertions(+), 42 deletions(-)
--
1.8.3.1
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