| Message ID | 20221031120443.78993-1-yuancan@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block/floppy: Fix memory leak in do_floppy_init() | expand |
Hello, On 10/31/22 16:04, Yuan Can wrote: > A memory leak was reported when floppy_alloc_disk() failed in > do_floppy_init(). > > unreferenced object 0xffff888115ed25a0 (size 8): > comm "modprobe", pid 727, jiffies 4295051278 (age 25.529s) > hex dump (first 8 bytes): > 00 ac 67 5b 81 88 ff ff ..g[.... > backtrace: > [<000000007f457abb>] __kmalloc_node+0x4c/0xc0 > [<00000000a87bfa9e>] blk_mq_realloc_tag_set_tags.part.0+0x6f/0x180 > [<000000006f02e8b1>] blk_mq_alloc_tag_set+0x573/0x1130 > [<0000000066007fd7>] 0xffffffffc06b8b08 > [<0000000081f5ac40>] do_one_initcall+0xd0/0x4f0 > [<00000000e26d04ee>] do_init_module+0x1a4/0x680 > [<000000001bb22407>] load_module+0x6249/0x7110 > [<00000000ad31ac4d>] __do_sys_finit_module+0x140/0x200 > [<000000007bddca46>] do_syscall_64+0x35/0x80 > [<00000000b5afec39>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 > unreferenced object 0xffff88810fc30540 (size 32): > comm "modprobe", pid 727, jiffies 4295051278 (age 25.529s) > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [<000000007f457abb>] __kmalloc_node+0x4c/0xc0 > [<000000006b91eab4>] blk_mq_alloc_tag_set+0x393/0x1130 > [<0000000066007fd7>] 0xffffffffc06b8b08 > [<0000000081f5ac40>] do_one_initcall+0xd0/0x4f0 > [<00000000e26d04ee>] do_init_module+0x1a4/0x680 > [<000000001bb22407>] load_module+0x6249/0x7110 > [<00000000ad31ac4d>] __do_sys_finit_module+0x140/0x200 > [<000000007bddca46>] do_syscall_64+0x35/0x80 > [<00000000b5afec39>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 > > If the floppy_alloc_disk() failed, disks of current drive will not be set, > thus the lastest allocated set->tag cannot be freed in the error handling > path. A simple call graph shown as below: > > floppy_module_init() > floppy_init() > do_floppy_init() > for (drive = 0; drive < N_DRIVE; drive++) > blk_mq_alloc_tag_set() > blk_mq_alloc_tag_set_tags() > blk_mq_realloc_tag_set_tags() # set->tag allocated > floppy_alloc_disk() > blk_mq_alloc_disk() # error occurred, disks failed to allocated > > ->out_put_disk: > for (drive = 0; drive < N_DRIVE; drive++) > if (!disks[drive][0]) # the last disks is not set and loop break > break; > blk_mq_free_tag_set() # the latest allocated set->tag leaked > > Fix this problem by free the set->tag of current drive before jump to > error handling path. > > Fixes: 302cfee15029 ("floppy: use a separate gendisk for each media format") > Signed-off-by: Yuan Can <yuancan@huawei.com> > --- Thank you for the patch! I took it to https://github.com/evdenis/linux-floppy/commit/b8c08b4dfa7c90860d77b980ce80382514452b2a and will send to Jens before 6.2 with other floppy fixes. I'll also send it to stable trees. > drivers/block/floppy.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c > index ccad3d7b3ddd..487840e3564d 100644 > --- a/drivers/block/floppy.c > +++ b/drivers/block/floppy.c > @@ -4593,8 +4593,10 @@ static int __init do_floppy_init(void) > goto out_put_disk; > > err = floppy_alloc_disk(drive, 0); > - if (err) > + if (err) { > + blk_mq_free_tag_set(&tag_sets[drive]); > goto out_put_disk; > + } > > timer_setup(&motor_off_timer[drive], motor_off_callback, 0); > } Thanks, Denis
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index ccad3d7b3ddd..487840e3564d 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -4593,8 +4593,10 @@ static int __init do_floppy_init(void) goto out_put_disk; err = floppy_alloc_disk(drive, 0); - if (err) + if (err) { + blk_mq_free_tag_set(&tag_sets[drive]); goto out_put_disk; + } timer_setup(&motor_off_timer[drive], motor_off_callback, 0); }
A memory leak was reported when floppy_alloc_disk() failed in do_floppy_init(). unreferenced object 0xffff888115ed25a0 (size 8): comm "modprobe", pid 727, jiffies 4295051278 (age 25.529s) hex dump (first 8 bytes): 00 ac 67 5b 81 88 ff ff ..g[.... backtrace: [<000000007f457abb>] __kmalloc_node+0x4c/0xc0 [<00000000a87bfa9e>] blk_mq_realloc_tag_set_tags.part.0+0x6f/0x180 [<000000006f02e8b1>] blk_mq_alloc_tag_set+0x573/0x1130 [<0000000066007fd7>] 0xffffffffc06b8b08 [<0000000081f5ac40>] do_one_initcall+0xd0/0x4f0 [<00000000e26d04ee>] do_init_module+0x1a4/0x680 [<000000001bb22407>] load_module+0x6249/0x7110 [<00000000ad31ac4d>] __do_sys_finit_module+0x140/0x200 [<000000007bddca46>] do_syscall_64+0x35/0x80 [<00000000b5afec39>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 unreferenced object 0xffff88810fc30540 (size 32): comm "modprobe", pid 727, jiffies 4295051278 (age 25.529s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000007f457abb>] __kmalloc_node+0x4c/0xc0 [<000000006b91eab4>] blk_mq_alloc_tag_set+0x393/0x1130 [<0000000066007fd7>] 0xffffffffc06b8b08 [<0000000081f5ac40>] do_one_initcall+0xd0/0x4f0 [<00000000e26d04ee>] do_init_module+0x1a4/0x680 [<000000001bb22407>] load_module+0x6249/0x7110 [<00000000ad31ac4d>] __do_sys_finit_module+0x140/0x200 [<000000007bddca46>] do_syscall_64+0x35/0x80 [<00000000b5afec39>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 If the floppy_alloc_disk() failed, disks of current drive will not be set, thus the lastest allocated set->tag cannot be freed in the error handling path. A simple call graph shown as below: floppy_module_init() floppy_init() do_floppy_init() for (drive = 0; drive < N_DRIVE; drive++) blk_mq_alloc_tag_set() blk_mq_alloc_tag_set_tags() blk_mq_realloc_tag_set_tags() # set->tag allocated floppy_alloc_disk() blk_mq_alloc_disk() # error occurred, disks failed to allocated ->out_put_disk: for (drive = 0; drive < N_DRIVE; drive++) if (!disks[drive][0]) # the last disks is not set and loop break break; blk_mq_free_tag_set() # the latest allocated set->tag leaked Fix this problem by free the set->tag of current drive before jump to error handling path. Fixes: 302cfee15029 ("floppy: use a separate gendisk for each media format") Signed-off-by: Yuan Can <yuancan@huawei.com> --- drivers/block/floppy.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)