Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 08/13/2013 11:16 AM, Douglas Gilbert wrote: On 13-08-12 10:46 PM, vaughan wrote: On 08/06/2013 04:52 AM, Douglas Gilbert wrote: On 13-08-04 10:19 PM, vaughan wrote: On 08/03/2013 01:25 PM, Douglas Gilbert wrote: On 13-08-01 01:01 AM, Douglas Gilbert wrote: On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Further testing suggests this patch on the sg driver is broken, so I'll rescind my ack. The case it is broken for is when a device is opened without O_EXCL. Now if, while it is open, a second thread/process tries to open the same device O_EXCL then IMO the second open should fail with EBUSY. My testing shows that O_EXCL opens properly deflect other O_EXCL opens. Hi Doug, My test don't have this issue. The routine is something as below: I start three opens without O_EXCL, wait 30s each, and open with O_EXCL|O_NONBLOCK, it failed with EBUSY. And I also call myopen with/without O_EXCL many times in background at the same time, and the test is passed. I don't know why it failed in your test. Usage: myopen [-e][-n][-d delay] -f file -e: exclude -n: nonblock -d: delay N seconds and then close. [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [1] 3417 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [2] 3418 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [3] 3419 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# ./myopen -e -n -f /dev/sg5 -d 30 [4] 3422 [3422:3351] /dev/sg5:exclude: Device or resource busy [4]+ Exit 1 ./myopen -e -n -f /dev/sg5 -d 30 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug [1] Done./myopen -f /dev/sg5 -d 30 [2]- Done./myopen -f /dev/sg5 -d 30 [3]+ Done./myopen -f /dev/sg5 -d 30 Hi, After the initial failures about 36 hours ago, retesting yesterday and today has not produced any unexpected failures. And I have been trying hard on lk 3.10.4 and lk 3.10.5 . My test program is a bit more intense than yours and can be found in the sg3_utils beta in the News section of this page: http://sg.danny.cz/sg/ It is in the examples directory, two variants called sg_tst_excl and sg_tst_excl2 . You will need a recent gcc compiler, IOW something that can compile c++11 . gcc 4.7.3 in Ubuntu 13.04 only just manages, fedora 19 should do better with gcc 4.8.1 . The threading is implemented using pthreads so it should be reliable. Typically I run
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 13-08-27 10:16 AM, vaughan wrote: On 08/13/2013 11:16 AM, Douglas Gilbert wrote: On 13-08-12 10:46 PM, vaughan wrote: On 08/06/2013 04:52 AM, Douglas Gilbert wrote: On 13-08-04 10:19 PM, vaughan wrote: On 08/03/2013 01:25 PM, Douglas Gilbert wrote: On 13-08-01 01:01 AM, Douglas Gilbert wrote: On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Further testing suggests this patch on the sg driver is broken, so I'll rescind my ack. The case it is broken for is when a device is opened without O_EXCL. Now if, while it is open, a second thread/process tries to open the same device O_EXCL then IMO the second open should fail with EBUSY. My testing shows that O_EXCL opens properly deflect other O_EXCL opens. Hi Doug, My test don't have this issue. The routine is something as below: I start three opens without O_EXCL, wait 30s each, and open with O_EXCL|O_NONBLOCK, it failed with EBUSY. And I also call myopen with/without O_EXCL many times in background at the same time, and the test is passed. I don't know why it failed in your test. Usage: myopen [-e][-n][-d delay] -f file -e: exclude -n: nonblock -d: delay N seconds and then close. [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [1] 3417 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [2] 3418 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [3] 3419 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# ./myopen -e -n -f /dev/sg5 -d 30 [4] 3422 [3422:3351] /dev/sg5:exclude: Device or resource busy [4]+ Exit 1 ./myopen -e -n -f /dev/sg5 -d 30 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug [1] Done./myopen -f /dev/sg5 -d 30 [2]- Done./myopen -f /dev/sg5 -d 30 [3]+ Done./myopen -f /dev/sg5 -d 30 Hi, After the initial failures about 36 hours ago, retesting yesterday and today has not produced any unexpected failures. And I have been trying hard on lk 3.10.4 and lk 3.10.5 . My test program is a bit more intense than yours and can be found in the sg3_utils beta in the News section of this page: http://sg.danny.cz/sg/ It is in the examples directory, two variants called sg_tst_excl and sg_tst_excl2 . You will need a recent gcc compiler, IOW something that can compile c++11 . gcc 4.7.3 in Ubuntu 13.04 only just manages, fedora 19 should do better with gcc 4.8.1 . The threading is implemented using pthreads so it should be reliable. Typically I run multiple instances (processes)
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 08/27/2013 09:13 PM, Douglas Gilbert wrote: On 13-08-27 10:16 AM, vaughan wrote: On 08/13/2013 11:16 AM, Douglas Gilbert wrote: On 13-08-12 10:46 PM, vaughan wrote: On 08/06/2013 04:52 AM, Douglas Gilbert wrote: On 13-08-04 10:19 PM, vaughan wrote: On 08/03/2013 01:25 PM, Douglas Gilbert wrote: On 13-08-01 01:01 AM, Douglas Gilbert wrote: On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Further testing suggests this patch on the sg driver is broken, so I'll rescind my ack. The case it is broken for is when a device is opened without O_EXCL. Now if, while it is open, a second thread/process tries to open the same device O_EXCL then IMO the second open should fail with EBUSY. My testing shows that O_EXCL opens properly deflect other O_EXCL opens. Hi Doug, My test don't have this issue. The routine is something as below: I start three opens without O_EXCL, wait 30s each, and open with O_EXCL|O_NONBLOCK, it failed with EBUSY. And I also call myopen with/without O_EXCL many times in background at the same time, and the test is passed. I don't know why it failed in your test. Usage: myopen [-e][-n][-d delay] -f file -e: exclude -n: nonblock -d: delay N seconds and then close. [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [1] 3417 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [2] 3418 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [3] 3419 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# ./myopen -e -n -f /dev/sg5 -d 30 [4] 3422 [3422:3351] /dev/sg5:exclude: Device or resource busy [4]+ Exit 1 ./myopen -e -n -f /dev/sg5 -d 30 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug [1] Done./myopen -f /dev/sg5 -d 30 [2]- Done./myopen -f /dev/sg5 -d 30 [3]+ Done./myopen -f /dev/sg5 -d 30 Hi, After the initial failures about 36 hours ago, retesting yesterday and today has not produced any unexpected failures. And I have been trying hard on lk 3.10.4 and lk 3.10.5 . My test program is a bit more intense than yours and can be found in the sg3_utils beta in the News section of this page: http://sg.danny.cz/sg/ It is in the examples directory, two variants called sg_tst_excl and sg_tst_excl2 . You will need a recent gcc compiler, IOW something that can compile c++11 . gcc 4.7.3 in Ubuntu 13.04 only just manages, fedora 19
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 08/06/2013 04:52 AM, Douglas Gilbert wrote: On 13-08-04 10:19 PM, vaughan wrote: On 08/03/2013 01:25 PM, Douglas Gilbert wrote: On 13-08-01 01:01 AM, Douglas Gilbert wrote: On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Further testing suggests this patch on the sg driver is broken, so I'll rescind my ack. The case it is broken for is when a device is opened without O_EXCL. Now if, while it is open, a second thread/process tries to open the same device O_EXCL then IMO the second open should fail with EBUSY. My testing shows that O_EXCL opens properly deflect other O_EXCL opens. Hi Doug, My test don't have this issue. The routine is something as below: I start three opens without O_EXCL, wait 30s each, and open with O_EXCL|O_NONBLOCK, it failed with EBUSY. And I also call myopen with/without O_EXCL many times in background at the same time, and the test is passed. I don't know why it failed in your test. Usage: myopen [-e][-n][-d delay] -f file -e: exclude -n: nonblock -d: delay N seconds and then close. [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [1] 3417 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [2] 3418 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [3] 3419 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# ./myopen -e -n -f /dev/sg5 -d 30 [4] 3422 [3422:3351] /dev/sg5:exclude: Device or resource busy [4]+ Exit 1 ./myopen -e -n -f /dev/sg5 -d 30 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug [1] Done./myopen -f /dev/sg5 -d 30 [2]- Done./myopen -f /dev/sg5 -d 30 [3]+ Done./myopen -f /dev/sg5 -d 30 Hi, After the initial failures about 36 hours ago, retesting yesterday and today has not produced any unexpected failures. And I have been trying hard on lk 3.10.4 and lk 3.10.5 . My test program is a bit more intense than yours and can be found in the sg3_utils beta in the News section of this page: http://sg.danny.cz/sg/ It is in the examples directory, two variants called sg_tst_excl and sg_tst_excl2 . You will need a recent gcc compiler, IOW something that can compile c++11 . gcc 4.7.3 in Ubuntu 13.04 only just manages, fedora 19 should do better with gcc 4.8.1 . The threading is implemented using pthreads so it should be reliable. Typically I run multiple instances (processes) and each has multiple threads. One instance can run '-x' which will cause its first thread not to use
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 13-08-12 10:46 PM, vaughan wrote: On 08/06/2013 04:52 AM, Douglas Gilbert wrote: On 13-08-04 10:19 PM, vaughan wrote: On 08/03/2013 01:25 PM, Douglas Gilbert wrote: On 13-08-01 01:01 AM, Douglas Gilbert wrote: On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Further testing suggests this patch on the sg driver is broken, so I'll rescind my ack. The case it is broken for is when a device is opened without O_EXCL. Now if, while it is open, a second thread/process tries to open the same device O_EXCL then IMO the second open should fail with EBUSY. My testing shows that O_EXCL opens properly deflect other O_EXCL opens. Hi Doug, My test don't have this issue. The routine is something as below: I start three opens without O_EXCL, wait 30s each, and open with O_EXCL|O_NONBLOCK, it failed with EBUSY. And I also call myopen with/without O_EXCL many times in background at the same time, and the test is passed. I don't know why it failed in your test. Usage: myopen [-e][-n][-d delay] -f file -e: exclude -n: nonblock -d: delay N seconds and then close. [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [1] 3417 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [2] 3418 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [3] 3419 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# ./myopen -e -n -f /dev/sg5 -d 30 [4] 3422 [3422:3351] /dev/sg5:exclude: Device or resource busy [4]+ Exit 1 ./myopen -e -n -f /dev/sg5 -d 30 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug [1] Done./myopen -f /dev/sg5 -d 30 [2]- Done./myopen -f /dev/sg5 -d 30 [3]+ Done./myopen -f /dev/sg5 -d 30 Hi, After the initial failures about 36 hours ago, retesting yesterday and today has not produced any unexpected failures. And I have been trying hard on lk 3.10.4 and lk 3.10.5 . My test program is a bit more intense than yours and can be found in the sg3_utils beta in the News section of this page: http://sg.danny.cz/sg/ It is in the examples directory, two variants called sg_tst_excl and sg_tst_excl2 . You will need a recent gcc compiler, IOW something that can compile c++11 . gcc 4.7.3 in Ubuntu 13.04 only just manages, fedora 19 should do better with gcc 4.8.1 . The threading is implemented using pthreads so it should be reliable. Typically I run multiple instances (processes) and each has multiple threads. One instance can run '-x' which will cause its first thread not to use O_EXCL **. All my tests
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 13-08-04 10:19 PM, vaughan wrote: On 08/03/2013 01:25 PM, Douglas Gilbert wrote: On 13-08-01 01:01 AM, Douglas Gilbert wrote: On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Further testing suggests this patch on the sg driver is broken, so I'll rescind my ack. The case it is broken for is when a device is opened without O_EXCL. Now if, while it is open, a second thread/process tries to open the same device O_EXCL then IMO the second open should fail with EBUSY. My testing shows that O_EXCL opens properly deflect other O_EXCL opens. Hi Doug, My test don't have this issue. The routine is something as below: I start three opens without O_EXCL, wait 30s each, and open with O_EXCL|O_NONBLOCK, it failed with EBUSY. And I also call myopen with/without O_EXCL many times in background at the same time, and the test is passed. I don't know why it failed in your test. Usage: myopen [-e][-n][-d delay] -f file -e: exclude -n: nonblock -d: delay N seconds and then close. [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [1] 3417 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [2] 3418 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [3] 3419 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# ./myopen -e -n -f /dev/sg5 -d 30 [4] 3422 [3422:3351] /dev/sg5:exclude: Device or resource busy [4]+ Exit 1 ./myopen -e -n -f /dev/sg5 -d 30 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug [1] Done./myopen -f /dev/sg5 -d 30 [2]- Done./myopen -f /dev/sg5 -d 30 [3]+ Done./myopen -f /dev/sg5 -d 30 Hi, After the initial failures about 36 hours ago, retesting yesterday and today has not produced any unexpected failures. And I have been trying hard on lk 3.10.4 and lk 3.10.5 . My test program is a bit more intense than yours and can be found in the sg3_utils beta in the News section of this page: http://sg.danny.cz/sg/ It is in the examples directory, two variants called sg_tst_excl and sg_tst_excl2 . You will need a recent gcc compiler, IOW something that can compile c++11 . gcc 4.7.3 in Ubuntu 13.04 only just manages, fedora 19 should do better with gcc 4.8.1 . The threading is implemented using pthreads so it should be reliable. Typically I run multiple instances (processes) and each has multiple threads. One instance can run '-x' which will cause its first thread not to use O_EXCL **. All my tests currently use O_NONBLOCK and that leads to lots of EBUSYs (sometimes in the billions). Doug Gilbert ** Using '-x' on two
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 08/03/2013 01:25 PM, Douglas Gilbert wrote: On 13-08-01 01:01 AM, Douglas Gilbert wrote: On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Further testing suggests this patch on the sg driver is broken, so I'll rescind my ack. The case it is broken for is when a device is opened without O_EXCL. Now if, while it is open, a second thread/process tries to open the same device O_EXCL then IMO the second open should fail with EBUSY. My testing shows that O_EXCL opens properly deflect other O_EXCL opens. Hi Doug, My test don't have this issue. The routine is something as below: I start three opens without O_EXCL, wait 30s each, and open with O_EXCL|O_NONBLOCK, it failed with EBUSY. And I also call myopen with/without O_EXCL many times in background at the same time, and the test is passed. I don't know why it failed in your test. Usage: myopen [-e][-n][-d delay] -f file -e: exclude -n: nonblock -d: delay N seconds and then close. [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [1] 3417 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [2] 3418 [root@vacaowol5 16835013]# ./myopen -f /dev/sg5 -d 30 [3] 3419 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# ./myopen -e -n -f /dev/sg5 -d 30 [4] 3422 [3422:3351] /dev/sg5:exclude: Device or resource busy [4]+ Exit 1 ./myopen -e -n -f /dev/sg5 -d 30 [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug max_active_device=6(origin 1) def_reserved_size=32768 device=sg5 scsi5 chan=0 id=1 lun=0 em=0 sg_tablesize=55 excl=0 FD(1): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(2): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active FD(3): timeout=6ms bufflen=32768 (res)sgat=1 low_dma=0 cmd_q=0 f_packid=0 k_orphan=0 closed=0 No requests active [root@vacaowol5 16835013]# cat /proc/scsi/sg/debug [1] Done./myopen -f /dev/sg5 -d 30 [2]- Done./myopen -f /dev/sg5 -d 30 [3]+ Done./myopen -f /dev/sg5 -d 30 BTW the standard block driver (e.g. /dev/sdc) is broken in exactly the same way, according to my tests. Doug Gilbert -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 13-08-01 01:01 AM, Douglas Gilbert wrote: On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Further testing suggests this patch on the sg driver is broken, so I'll rescind my ack. The case it is broken for is when a device is opened without O_EXCL. Now if, while it is open, a second thread/process tries to open the same device O_EXCL then IMO the second open should fail with EBUSY. My testing shows that O_EXCL opens properly deflect other O_EXCL opens. BTW the standard block driver (e.g. /dev/sdc) is broken in exactly the same way, according to my tests. Doug Gilbert -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 13-07-22 01:03 PM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Acked-by: Douglas Gilbert dgilb...@interlog.com Tested O_EXCL with multiple processes and threads; passed. sg driver prior to this patch had leaky O_EXCL logic according to the same test. Block device passed. James, could you clean this up: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] Doug Gilbert -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 07/26/2013 04:33 AM, Douglas Gilbert wrote: On 13-07-25 11:32 AM, vaughan wrote: On 07/23/2013 01:03 AM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Jörn Hi James, sg driver has two races happen in a) exclusive open and non-exclusive open b) sg removal and sg open I explained the scenario detail in the separate patches. I did test those patches and Jörn has reviewed them. I got no response from Doug Gilbert for a long time. Would you care to pick these up? Hi, Your patches applied with a little noise to lk 3.10.2 and gave this warning from the build. CC [M] drivers/scsi/sg.o drivers/scsi/sg.c: In function ‘sg_open’: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] I'll keep testing ... Hi Doug, Can I ask how about the test result? Thanks, Vaughan Doug Gilbert -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 07/23/2013 01:03 AM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Jörn Hi James, sg driver has two races happen in a) exclusive open and non-exclusive open b) sg removal and sg open I explained the scenario detail in the separate patches. I did test those patches and Jörn has reviewed them. I got no response from Doug Gilbert for a long time. Would you care to pick these up? Thanks, Vaughan -- Good warriors cause others to come to them and do not go to others. -- Sun Tzu -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On 13-07-25 11:32 AM, vaughan wrote: On 07/23/2013 01:03 AM, Jörn Engel wrote: On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Jörn Hi James, sg driver has two races happen in a) exclusive open and non-exclusive open b) sg removal and sg open I explained the scenario detail in the separate patches. I did test those patches and Jörn has reviewed them. I got no response from Doug Gilbert for a long time. Would you care to pick these up? Hi, Your patches applied with a little noise to lk 3.10.2 and gave this warning from the build. CC [M] drivers/scsi/sg.o drivers/scsi/sg.c: In function ‘sg_open’: drivers/scsi/sg.c:242:6: warning: unused variable ‘res’ [-Wunused-variable] I'll keep testing ... Doug Gilbert -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
On Mon, 22 July 2013 12:40:29 +0800, Vaughan Cao wrote: There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) Patchset looks good to me, although I didn't test it on hardware yet. Signed-off-by: Joern Engel jo...@logfs.org James, care to pick this up? Jörn -- Good warriors cause others to come to them and do not go to others. -- Sun Tzu -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH v5 0/4] [SCSI] sg: fix race condition in sg_open
There is a race when open sg with O_EXCL flag. Also a race may happen between sg_open and sg_remove. Changes from v4: * [3/4] use ERR_PTR series instead of adding another parameter in sg_add_sfp * [4/4] fix conflict for cherry-pick from v3. Changes from v3: * release o_sem in sg_release(), not in sg_remove_sfp(). * not set exclude with sfd_lock held. Vaughan Cao (4): [SCSI] sg: use rwsem to solve race during exclusive open [SCSI] sg: no need sg_open_exclusive_lock [SCSI] sg: checking sdp-detached isn't protected when open [SCSI] sg: push file descriptor list locking down to per-device locking drivers/scsi/sg.c | 178 +- 1 file changed, 83 insertions(+), 95 deletions(-) -- 1.7.11.7 -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html