| Message ID | 20190115225447.75212-1-swboyd@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] soc: qcom: rpmh: Avoid accessing freed memory from batch API | expand |
On Tue, Jan 15 2019 at 15:54 -0700, Stephen Boyd wrote: >Using the batch API from the interconnect driver sometimes leads to a >KASAN error due to an access to freed memory. This is easier to trigger >with threadirqs on the kernel commandline. > > BUG: KASAN: use-after-free in rpmh_tx_done+0x114/0x12c > Read of size 1 at addr fffffff51414ad84 by task irq/110-apps_rs/57 > > CPU: 0 PID: 57 Comm: irq/110-apps_rs Tainted: G W 4.19.10 #72 > Call trace: > dump_backtrace+0x0/0x2f8 > show_stack+0x20/0x2c > __dump_stack+0x20/0x28 > dump_stack+0xcc/0x10c > print_address_description+0x74/0x240 > kasan_report+0x250/0x26c > __asan_report_load1_noabort+0x20/0x2c > rpmh_tx_done+0x114/0x12c > tcs_tx_done+0x450/0x768 > irq_forced_thread_fn+0x58/0x9c > irq_thread+0x120/0x1dc > kthread+0x248/0x260 > ret_from_fork+0x10/0x18 > > Allocated by task 385: > kasan_kmalloc+0xac/0x148 > __kmalloc+0x170/0x1e4 > rpmh_write_batch+0x174/0x540 > qcom_icc_set+0x8dc/0x9ac > icc_set+0x288/0x2e8 > a6xx_gmu_stop+0x320/0x3c0 > a6xx_pm_suspend+0x108/0x124 > adreno_suspend+0x50/0x60 > pm_generic_runtime_suspend+0x60/0x78 > __rpm_callback+0x214/0x32c > rpm_callback+0x54/0x184 > rpm_suspend+0x3f8/0xa90 > pm_runtime_work+0xb4/0x178 > process_one_work+0x544/0xbc0 > worker_thread+0x514/0x7d0 > kthread+0x248/0x260 > ret_from_fork+0x10/0x18 > > Freed by task 385: > __kasan_slab_free+0x12c/0x1e0 > kasan_slab_free+0x10/0x1c > kfree+0x134/0x588 > rpmh_write_batch+0x49c/0x540 > qcom_icc_set+0x8dc/0x9ac > icc_set+0x288/0x2e8 > a6xx_gmu_stop+0x320/0x3c0 > a6xx_pm_suspend+0x108/0x124 > adreno_suspend+0x50/0x60 > cr50_spi spi5.0: SPI transfer timed out > pm_generic_runtime_suspend+0x60/0x78 > __rpm_callback+0x214/0x32c > rpm_callback+0x54/0x184 > rpm_suspend+0x3f8/0xa90 > pm_runtime_work+0xb4/0x178 > process_one_work+0x544/0xbc0 > worker_thread+0x514/0x7d0 > kthread+0x248/0x260 > ret_from_fork+0x10/0x18 > > The buggy address belongs to the object at fffffff51414ac80 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 260 bytes inside of > 512-byte region [fffffff51414ac80, fffffff51414ae80) > The buggy address belongs to the page: > page:ffffffbfd4505200 count:1 mapcount:0 mapping:fffffff51e00c680 index:0x0 compound_mapcount: 0 > flags: 0x4000000000008100(slab|head) > raw: 4000000000008100 ffffffbfd4529008 ffffffbfd44f9208 fffffff51e00c680 > raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > fffffff51414ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > fffffff51414ad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >fffffff51414ad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > fffffff51414ae00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > fffffff51414ae80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > >The batch API sets the same completion for each rpmh message that's sent >and then loops through all the messages and waits for that single >completion declared on the stack to be completed before returning from >the function and freeing the message structures. Unfortunately, some >messages may still be in process and 'stuck' in the TCS. At some later >point, the tcs_tx_done() interrupt will run and try to process messages >that have already been freed at the end of rpmh_write_batch(). This will >in turn access the 'needs_free' member of the rpmh_request structure and >cause KASAN to complain. Furthermore, if there's a message that's >completed in rpmh_tx_done() and freed immediately after the complete() >call is made we'll be racing with potentially freed memory when >accessing the 'needs_free' member: > > CPU0 CPU1 > ---- ---- > rpmh_tx_done() > complete(&compl) > wait_for_completion(&compl) > kfree(rpm_msg) > if (rpm_msg->needs_free) > <KASAN warning splat> > >Let's fix this by allocating a chunk of completions for each message and >waiting for all of them to be completed before returning from the batch >API. Alternatively, we could wait for the last message in the batch, but >that may be a more complicated change because it looks like >tcs_tx_done() just iterates through the indices of the queue and >completes each message instead of tracking the last inserted message and >completing that first. > >Cc: Lina Iyer <ilina@codeaurora.org> >Cc: "Raju P.L.S.S.S.N" <rplsssn@codeaurora.org> >Cc: Matthias Kaehlcke <mka@chromium.org> >Cc: Evan Green <evgreen@chromium.org> >Fixes: c8790cb6da58 ("drivers: qcom: rpmh: add support for batch RPMH request") >Signed-off-by: Stephen Boyd <swboyd@chromium.org> Reviewed-by: Lina Iyer <ilina@codeaurora.org> >--- > >Changes from v1: > * Incorporated needs_free check earlier > * Simplified logic to no longer flush everything out on failure > > drivers/soc/qcom/rpmh.c | 34 +++++++++++++++++++++------------- > 1 file changed, 21 insertions(+), 13 deletions(-) > >diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c >index c7beb6841289..ab8f731a3426 100644 >--- a/drivers/soc/qcom/rpmh.c >+++ b/drivers/soc/qcom/rpmh.c >@@ -80,6 +80,7 @@ void rpmh_tx_done(const struct tcs_request *msg, int r) > struct rpmh_request *rpm_msg = container_of(msg, struct rpmh_request, > msg); > struct completion *compl = rpm_msg->completion; >+ bool free = rpm_msg->needs_free; > > rpm_msg->err = r; > >@@ -94,7 +95,7 @@ void rpmh_tx_done(const struct tcs_request *msg, int r) > complete(compl); > > exit: >- if (rpm_msg->needs_free) >+ if (free) > kfree(rpm_msg); > } > >@@ -348,11 +349,12 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, > { > struct batch_cache_req *req; > struct rpmh_request *rpm_msgs; >- DECLARE_COMPLETION_ONSTACK(compl); >+ struct completion *compls; > struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev); > unsigned long time_left; > int count = 0; >- int ret, i, j; >+ int ret, i; >+ void *ptr; > > if (!cmd || !n) > return -EINVAL; >@@ -362,10 +364,15 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, > if (!count) > return -EINVAL; > >- req = kzalloc(sizeof(*req) + count * sizeof(req->rpm_msgs[0]), >+ ptr = kzalloc(sizeof(*req) + >+ count * (sizeof(req->rpm_msgs[0]) + sizeof(*compls)), > GFP_ATOMIC); >- if (!req) >+ if (!ptr) > return -ENOMEM; >+ >+ req = ptr; >+ compls = ptr + sizeof(*req) + count * sizeof(*rpm_msgs); >+ > req->count = count; > rpm_msgs = req->rpm_msgs; > >@@ -380,25 +387,26 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, > } > > for (i = 0; i < count; i++) { >- rpm_msgs[i].completion = &compl; >+ struct completion *compl = &compls[i]; >+ >+ init_completion(compl); >+ rpm_msgs[i].completion = compl; > ret = rpmh_rsc_send_data(ctrlr_to_drv(ctrlr), &rpm_msgs[i].msg); > if (ret) { > pr_err("Error(%d) sending RPMH message addr=%#x\n", > ret, rpm_msgs[i].msg.cmds[0].addr); >- for (j = i; j < count; j++) >- rpmh_tx_done(&rpm_msgs[j].msg, ret); > break; > } > } > > time_left = RPMH_TIMEOUT_MS; >- for (i = 0; i < count; i++) { >- time_left = wait_for_completion_timeout(&compl, time_left); >+ while (i--) { >+ time_left = wait_for_completion_timeout(&compls[i], time_left); > if (!time_left) { > /* > * Better hope they never finish because they'll signal >- * the completion on our stack and that's bad once >- * we've returned from the function. >+ * the completion that we're going to free once >+ * we've returned from this function. > */ > WARN_ON(1); > ret = -ETIMEDOUT; >@@ -407,7 +415,7 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, > } > > exit: >- kfree(req); >+ kfree(ptr); > > return ret; > } >-- >Sent by a computer through tubes >
On Tue, Jan 15, 2019 at 2:54 PM Stephen Boyd <swboyd@chromium.org> wrote: > > Using the batch API from the interconnect driver sometimes leads to a > KASAN error due to an access to freed memory. This is easier to trigger > with threadirqs on the kernel commandline. > > BUG: KASAN: use-after-free in rpmh_tx_done+0x114/0x12c > Read of size 1 at addr fffffff51414ad84 by task irq/110-apps_rs/57 > > CPU: 0 PID: 57 Comm: irq/110-apps_rs Tainted: G W 4.19.10 #72 > Call trace: > dump_backtrace+0x0/0x2f8 > show_stack+0x20/0x2c > __dump_stack+0x20/0x28 > dump_stack+0xcc/0x10c > print_address_description+0x74/0x240 > kasan_report+0x250/0x26c > __asan_report_load1_noabort+0x20/0x2c > rpmh_tx_done+0x114/0x12c > tcs_tx_done+0x450/0x768 > irq_forced_thread_fn+0x58/0x9c > irq_thread+0x120/0x1dc > kthread+0x248/0x260 > ret_from_fork+0x10/0x18 > > Allocated by task 385: > kasan_kmalloc+0xac/0x148 > __kmalloc+0x170/0x1e4 > rpmh_write_batch+0x174/0x540 > qcom_icc_set+0x8dc/0x9ac > icc_set+0x288/0x2e8 > a6xx_gmu_stop+0x320/0x3c0 > a6xx_pm_suspend+0x108/0x124 > adreno_suspend+0x50/0x60 > pm_generic_runtime_suspend+0x60/0x78 > __rpm_callback+0x214/0x32c > rpm_callback+0x54/0x184 > rpm_suspend+0x3f8/0xa90 > pm_runtime_work+0xb4/0x178 > process_one_work+0x544/0xbc0 > worker_thread+0x514/0x7d0 > kthread+0x248/0x260 > ret_from_fork+0x10/0x18 > > Freed by task 385: > __kasan_slab_free+0x12c/0x1e0 > kasan_slab_free+0x10/0x1c > kfree+0x134/0x588 > rpmh_write_batch+0x49c/0x540 > qcom_icc_set+0x8dc/0x9ac > icc_set+0x288/0x2e8 > a6xx_gmu_stop+0x320/0x3c0 > a6xx_pm_suspend+0x108/0x124 > adreno_suspend+0x50/0x60 > cr50_spi spi5.0: SPI transfer timed out > pm_generic_runtime_suspend+0x60/0x78 > __rpm_callback+0x214/0x32c > rpm_callback+0x54/0x184 > rpm_suspend+0x3f8/0xa90 > pm_runtime_work+0xb4/0x178 > process_one_work+0x544/0xbc0 > worker_thread+0x514/0x7d0 > kthread+0x248/0x260 > ret_from_fork+0x10/0x18 > > The buggy address belongs to the object at fffffff51414ac80 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 260 bytes inside of > 512-byte region [fffffff51414ac80, fffffff51414ae80) > The buggy address belongs to the page: > page:ffffffbfd4505200 count:1 mapcount:0 mapping:fffffff51e00c680 index:0x0 compound_mapcount: 0 > flags: 0x4000000000008100(slab|head) > raw: 4000000000008100 ffffffbfd4529008 ffffffbfd44f9208 fffffff51e00c680 > raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > fffffff51414ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > fffffff51414ad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >fffffff51414ad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > fffffff51414ae00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > fffffff51414ae80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > The batch API sets the same completion for each rpmh message that's sent > and then loops through all the messages and waits for that single > completion declared on the stack to be completed before returning from > the function and freeing the message structures. Unfortunately, some > messages may still be in process and 'stuck' in the TCS. At some later > point, the tcs_tx_done() interrupt will run and try to process messages > that have already been freed at the end of rpmh_write_batch(). This will > in turn access the 'needs_free' member of the rpmh_request structure and > cause KASAN to complain. Furthermore, if there's a message that's > completed in rpmh_tx_done() and freed immediately after the complete() > call is made we'll be racing with potentially freed memory when > accessing the 'needs_free' member: > > CPU0 CPU1 > ---- ---- > rpmh_tx_done() > complete(&compl) > wait_for_completion(&compl) > kfree(rpm_msg) > if (rpm_msg->needs_free) > <KASAN warning splat> > > Let's fix this by allocating a chunk of completions for each message and > waiting for all of them to be completed before returning from the batch > API. Alternatively, we could wait for the last message in the batch, but > that may be a more complicated change because it looks like > tcs_tx_done() just iterates through the indices of the queue and > completes each message instead of tracking the last inserted message and > completing that first. > > Cc: Lina Iyer <ilina@codeaurora.org> > Cc: "Raju P.L.S.S.S.N" <rplsssn@codeaurora.org> > Cc: Matthias Kaehlcke <mka@chromium.org> > Cc: Evan Green <evgreen@chromium.org> > Fixes: c8790cb6da58 ("drivers: qcom: rpmh: add support for batch RPMH request") > Signed-off-by: Stephen Boyd <swboyd@chromium.org> > --- > > Changes from v1: > * Incorporated needs_free check earlier > * Simplified logic to no longer flush everything out on failure > > drivers/soc/qcom/rpmh.c | 34 +++++++++++++++++++++------------- > 1 file changed, 21 insertions(+), 13 deletions(-) > Reviewed-by: Evan Green <evgreen@chromium.org>
diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c index c7beb6841289..ab8f731a3426 100644 --- a/drivers/soc/qcom/rpmh.c +++ b/drivers/soc/qcom/rpmh.c @@ -80,6 +80,7 @@ void rpmh_tx_done(const struct tcs_request *msg, int r) struct rpmh_request *rpm_msg = container_of(msg, struct rpmh_request, msg); struct completion *compl = rpm_msg->completion; + bool free = rpm_msg->needs_free; rpm_msg->err = r; @@ -94,7 +95,7 @@ void rpmh_tx_done(const struct tcs_request *msg, int r) complete(compl); exit: - if (rpm_msg->needs_free) + if (free) kfree(rpm_msg); } @@ -348,11 +349,12 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, { struct batch_cache_req *req; struct rpmh_request *rpm_msgs; - DECLARE_COMPLETION_ONSTACK(compl); + struct completion *compls; struct rpmh_ctrlr *ctrlr = get_rpmh_ctrlr(dev); unsigned long time_left; int count = 0; - int ret, i, j; + int ret, i; + void *ptr; if (!cmd || !n) return -EINVAL; @@ -362,10 +364,15 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, if (!count) return -EINVAL; - req = kzalloc(sizeof(*req) + count * sizeof(req->rpm_msgs[0]), + ptr = kzalloc(sizeof(*req) + + count * (sizeof(req->rpm_msgs[0]) + sizeof(*compls)), GFP_ATOMIC); - if (!req) + if (!ptr) return -ENOMEM; + + req = ptr; + compls = ptr + sizeof(*req) + count * sizeof(*rpm_msgs); + req->count = count; rpm_msgs = req->rpm_msgs; @@ -380,25 +387,26 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, } for (i = 0; i < count; i++) { - rpm_msgs[i].completion = &compl; + struct completion *compl = &compls[i]; + + init_completion(compl); + rpm_msgs[i].completion = compl; ret = rpmh_rsc_send_data(ctrlr_to_drv(ctrlr), &rpm_msgs[i].msg); if (ret) { pr_err("Error(%d) sending RPMH message addr=%#x\n", ret, rpm_msgs[i].msg.cmds[0].addr); - for (j = i; j < count; j++) - rpmh_tx_done(&rpm_msgs[j].msg, ret); break; } } time_left = RPMH_TIMEOUT_MS; - for (i = 0; i < count; i++) { - time_left = wait_for_completion_timeout(&compl, time_left); + while (i--) { + time_left = wait_for_completion_timeout(&compls[i], time_left); if (!time_left) { /* * Better hope they never finish because they'll signal - * the completion on our stack and that's bad once - * we've returned from the function. + * the completion that we're going to free once + * we've returned from this function. */ WARN_ON(1); ret = -ETIMEDOUT; @@ -407,7 +415,7 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, } exit: - kfree(req); + kfree(ptr); return ret; }